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Food is the primary substance needed by humans to survive. However, food is easily contaminated by spoilage bacteria, which cause a decrease in quality and shelf life. Moreover, spoilage bacteria in food can be pathogenic, leading to foodborne disease that endangers human health. This issue has also driven the widespread use of synthetic preservatives, which have negative effects both in the short and long term. Biopreservation efforts utilizing bacteriocins produced by lactic acid bacteria offer an alternative solution to prevent spoilage and extend the shelf life of food. These bacteriocins are safe to use as they are produced by lactic acid bacteria that are approved for use in food. The application of various types of bacteriocins as biopreservatives has been widely conducted. Several other types of bacteriocins are continuously being researched and developed to ensure their safety and suitability for use as food biopreservatives. This article highlights bacteriocins, including their classification, general overview, mechanisms of action, differences from antibiotics, diversity, applications, prospects, and challenges as future food biopreservatives. Additionally, this article presents commercial bacteriocins, namely, nisin and pediocin, which are frequently used for food preservation. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) are known to exhibit various beneficial roles in fermentation, serving as probiotics, and producing a plethora of valuable compounds including antimicrobial activity such as bacteriocin-like inhibitory substance (BLIS) that can be used as biopreservative to improve food safety and quality. However, the yield of BLIS is often limited, which poses a challenge to be commercially competitive with the current preservation practice. Therefore, the present work aimed to establish an optimised two-plasmid CRISPR/Cas9 system to redirect the carbon flux away from lactate towards compounds with antimicrobial activity by disrupting lactate dehydrogenase gene (ldh) on various strains of LAB. The lactic acid-deficient (ldhΔ) strains caused a metabolic shift resulting in increased inhibitory activity against selected foodborne pathogens up to 78 % than the wild-type (WT) strain. The most significant effect was depicted by Enterococcus faecalis-ldh∆ which displayed prominent bactericidal effects against all foodborne pathogens as compared to the WT that showed no antimicrobial activity. The present work provided a framework model for economically important LAB and other beneficial bacteria to synthesise and increase the yield of valuable food and industrial compounds. The present work reported for the first time that the metabolism of selected LAB can be manipulated by modifying ldh to attain metabolites with higher antimicrobial activity. • The development of a new mutant lactic acid bacteria (LAB) strains was attained by genetically disrupt lactate dehydrogenase (ldh) gene, to eliminate the production of lactic acid. • The deletion of the ldh was achieved by introducing an efficient two-plasmid CRISPR system. • The growth rate of the mutant LAB strains show significant changes due to the deletion of ldh. • The effects of metabolic alteration on Bacteriocin-Like Inhibitory Substance (BLIS) was significantly increase up to two-fold resulted from re-routing of the carbon flow towards BLIS pathway. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) can produce peptides known as bacteriocins with antagonistic activity against foodborne pathogens. The potential of LAB isolated from the surface of jalapeno peppers to produce bacteriocins with antagonistic activity against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella Typhimurium was evaluated. Previously isolated LAB strains were reactivated, and their cell-free supernatants (CFSs) were evaluated. Out of 390 reactivated strains, 60 produced bacteriocin-like inhibitory substances (BLIS) since their antagonistic activity was lost after proteases addition. Subsequently, 16 BLIS showed heat resistance (HR-BLIS), retaining their bioactivity after heat treatment (121 °C for 15 min). By 16S rRNA gene sequencing and antibiotic susceptibility tests, LAB strains producing HR-BLIS were identified as Enterococcus lactis. Four HR-BLIS exhibited a minimum inhibitory concentration (MIC) of 80 mg/mL against L. monocytogenes. MIC and minimum bactericidal concentration (MBC) of HR-BLIS-67 for S. aureus (MIC = 80 mg/mL; MBC = 320 mg/mL), S. Typhimurium (MIC = 150 mg/mL; MBC = 250 mg/mL), and E. coli O157:H7 (MIC = 250 mg/mL; MBC = 400 mg/mL) were determined. LAB isolated from the surface of jalapeno pepper produced HR-BLIS (possibly enterocin) that exhibited broad-spectrum antagonistic activity against foodborne pathogens; therefore, they are a promising source of natural antimicrobials to ensure food safety.

Food spoilage fungi are becoming a global challenge to food storage and food safety, hence tons of food are lost annually to the activities of these fungi while consumption of spoilt food are dangerous to human health. Therefore, the objective of this paper is to assess the antifungal activities of lemon grass oil (Cymbopogon citratus) against some food spoilage fungi using different standard techniques such as dilution plating technique, colonial and morphological characterization. Oil extraction was done using fractional distillation method and biocompounds evaluation with GC-MS, antifungal activity, the minimum inhibitory (MI) and fungicidal concentrations (MFC) were determine using standard methods. Results show that five fungi were identified as Aspergillus niger, Penicillum sp., Aspergillus oryzae, Aspergillus flavusand Aspergillus terreus. The GC-MS of the oil detectscitral, citronellol, neral, geranial, limonene and geranyl acetate, flavonoids, alcohol and terpenoids. The oil was cidal to 100 % of the fungi at stock concentration. The minimum inhibitory concentrations against Aspergillus niger, Aspergillus oryzae and Aspergillus terreus was 0.781 µL/ml, Penicillumsp. 0.391µL/ml, and Aspergillus flavus, 6.25µL/ml. The MFC for Aspergillus nigerwas 1.563µL/ml, 0.781µL/ml for Penicillumsp and Aspergillus oryzae 6.25µL/ml for Aspergillus flavus and 1.563 µL/ml for Aspergillust erreus. Lemon grass oil extracted was active against common food spoilage fungi examined and could be a potential biopreservative and antifungal agent. [ABSTRACT FROM AUTHOR]

This study presents an innovative approach to enhancing the shelf life and maintaining the quality of sliced cooked ham through the application of a natural biopreservative derived from lactic fermentation. The biopreservative, at concentrations ranging from 1% to 3.5%, demonstrated substantial efficacy in microbial inhibition, keeping the microbial density low and relatively constant over time (p < 0.05). Remarkably, even at the lower concentration of 1%, the microbial growth rates were significantly reduced, with the treated samples showing notable stability over 24 days at both 7 °C and 25 °C. The microbial count in the treated with biopreservative group was significantly lower (3.19 log cfu/g) compared to the blank (4.59 log cfu/g) and control (5.01 log cfu/g) over 4 days at 7 °C. The shelf life of the ham was 24 days for the blank, 20 days for the control, and 101 days for the treated group at 7 °C. Moreover, colorimetric analysis revealed that the treated samples maintained better color stability, experiencing less variation in the hue angle and chroma, suggesting a protective effect against quality degradation over time. The successful application of the biopreservative aligns with the growing consumer demand for natural food additives and underscores the movement toward sustainable, health-conscious food preservation practices. The findings of this study indicate a promising avenue for the food industry to adopt environmentally friendly alternatives to synthetic additives, which could significantly influence future standards in food processing and preservation. [ABSTRACT FROM AUTHOR]

Although some Bacillus (B.) species have been reported to produce bacteriocins, their study and application are limited. In this study, we partially purified and characterized bacteriocins from two Bacillus strains isolated from Thai fermented soybeans. Then, we evaluated the effectiveness of one of the bacteriocins in controlling the growth of a Gram-positive spoilage bacterium (LactoBacillus plantarum) in soybean curd (tofu) and a pathogen (Listeria monocytogenes) in an edible cricket. In five candidate Bacillus strains, one B. subtilis strain (T8434) and one B. velezensis (T8448) strain produced heat-resistant bacteriocins that were effective in controlling the growth of several Gram-positive bacteria. Partially purified bacteriocins produced by these strains were heat stable (95 °C for 10 min), were sensitive to proteinase K digestion, harbored a negative charge at neutral pH, and were smaller than 10kDa in molecular mass. The bacteriocins suppressed the growth of inoculated spoilage lactic acid bacteria (LAB), which is LactoBacillus plantarum in soybean curd (tofu) and inoculated pathogenic Gram-positive bacteria (Listeria monocytogenes) in the edible cricket for 7 and 2 days at 10 °C, respectively. The Bacillus bacteriocins were considered to have the potential to control the growth of Gram-positive spoilage and pathogenic bacteria in solid foods. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) can produce peptides known as bacteriocins with antagonistic activity against foodborne pathogens. The potential of LAB isolated from the surface of jalapeno peppers to produce bacteriocins with antagonistic activity against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella Typhimurium was evaluated. Previously isolated LAB strains were reactivated, and their cell-free supernatants (CFSs) were evaluated. Out of 390 reactivated strains, 60 produced bacteriocin-like inhibitory substances (BLIS) since their antagonistic activity was lost after proteases addition. Subsequently, 16 BLIS showed heat resistance (HR-BLIS), retaining their bioactivity after heat treatment (121 °C for 15 min). By 16S rRNA gene sequencing and antibiotic susceptibility tests, LAB strains producing HR-BLIS were identified as Enterococcus lactis. Four HR-BLIS exhibited a minimum inhibitory concentration (MIC) of 80 mg/mL against L. monocytogenes. MIC and minimum bactericidal concentration (MBC) of HR-BLIS-67 for S. aureus (MIC = 80 mg/mL; MBC = 320 mg/mL), S. Typhimurium (MIC = 150 mg/mL; MBC = 250 mg/mL), and E. coli O157:H7 (MIC = 250 mg/mL; MBC = 400 mg/mL) were determined. LAB isolated from the surface of jalapeno pepper produced HR-BLIS (possibly enterocin) that exhibited broad-spectrum antagonistic activity against foodborne pathogens; therefore, they are a promising source of natural antimicrobials to ensure food safety. [ABSTRACT FROM AUTHOR]

Fresh-cut vegetables are widely consumed, but there is no food preservative available to selectively inhibit vancomycin-resistant E. faecalis, which is a serious health menace in fresh-cut vegetables. To develop a promising food biopreservative, a bacteriocin, paracin wx7, was synthesized, showing selective inhibition against E. faecalis with MIC values of 4–8 μM. It showed instant bactericidal mode within 1 h at high concentrations with concomitant cell lysis against vancomycin-resistant E. faecalis. Its lethal effect was visualized in a dose-dependent manner by PI/SYTO9 staining observation. The results of an in vivo control experiment carried out on E. faecalis in fresh-cut lettuce showed that 99.97% of vancomycin-resistant E. faecalis were dead after 64 μM paracin wx7 treatment for 7 days without influencing total bacteria. Further, the action mechanism of paracin wx7 was investigated. Confocal microscopy showed that paracin wx7 was located both on the cell envelope and in cytoplasm. For the cell envelope, the studies of membrane permeability using SYTOX Green dyeing and DNA leakage revealed that paracin wx7 damaged the membrane integrity of E. faecalis. Simultaneously, it exhibited membrane depolarization after analysis using DiSC3(5). Damage to the cell envelope resulted in cell deformation observed by scanning electron microscopy. On entering the cytoplasm, the paracin wx7 induced the production of endogenous reactive oxygen species. [ABSTRACT FROM AUTHOR]

Food spoilage fungi are becoming a global challenge to food storage and food safety, hence tons of food are lost annually to the activities of these fungi while consumption of spoilt food are dangerous to human health. Therefore, the objective of this paper is to assess the antifungal activities of lemon grass oil (Cymbopogon citratus) against some food spoilage fungi using different standard techniques such as dilution plating technique, colonial and morphological characterization. Oil extraction was done using fractional distillation method and biocompounds evaluation with GC-MS, antifungal activity, the minimum inhibitory (MI) and fungicidal concentrations (MFC) were determine using standard methods. Results show that five fungi were identified as Aspergillus niger, Penicillum sp., Aspergillus oryzae, Aspergillus flavusand Aspergillus terreus. The GC-MS of the oil detectscitral, citronellol, neral, geranial, limonene and geranyl acetate, flavonoids, alcohol and terpenoids. The oil was cidal to 100 % of the fungi at stock concentration. The minimum inhibitory concentrations against Aspergillus niger, Aspergillus oryzae and Aspergillus terreus was 0.781 μL/ml, Penicillumsp. 0.391μL/ml, and Aspergillus flavus, 6.25μL/ml. The MFC for Aspergillus nigerwas 1.563μL/ml, 0.781μL/ml for Penicillumsp and Aspergillus oryzae 6.25μL/ml for Aspergillus flavus and 1.563 μL/ml for Aspergillust erreus. Lemon grass oil extracted was active against common food spoilage fungi examined and could be a potential biopreservative and antifungal agent.

The influence of environmental factors on Salmonella sensitivity to nisin in vitro and in refrigerated orange juice were investigated. Nisin activity was observed in the different conditions, but the highest efficiency was achieved at lower pH (4.0) and with higher bacteriocin concentration (174 µM). Moreover, the bactericidal action was directly proportional to the incubation period. When tested in orange juice, nisin caused a reduction of up to 4.05 logarithm cycles in the Salmonella population. So, environmental factors such as low pH and low temperature favored the sensitization of Salmonella cells to the bactericidal action of nisin. Therefore, this may represent an alternative to control Salmonella in refrigerated foods. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate the usage possibilities of P. terebinthus fruit, which has a limited usage area, in the food industry. Antimicrobial activity of hexane extract obtained from P. terebinthus fruits from Adıyaman (Turkey) was determined by disc diffusion and micro-dilution assays against test microorganisms. In addition, the antibacterial activity of the extract on Escherichia coli O157:H7, one of the most important food-borne pathogens, was determined by viable cell count using a macro-dilution assay. The potential for use of the extract with probiotic candidate lactic acid bacteria (LAB) strains was also investigated. The hexane extract presented antimicrobial activity against all the tested microorganisms, with good inhibition zone diameters between 10.51 mm and 18.02 mm. MIC and MFC or MBC values of P. terebinthus fruit extract were determined as 5-80 µg/µL against all tested microorganisms. The lowest MIC and MBC values (5 µg/µL) of the extract were obtained against E. coli O157:H7. Macro-dilution assay results indicated that the P. terebinthus extract at various concentrations (5-10-20 mg/mL) inhibited the growth of E. coli O157:H7 more than the control group after all of the incubation hours. No viable E. coli O157:H7 cells were detected after 48 hours at all concentrations. The extract showed low antimicrobial activity, and relatively high bactericidal concentration on probiotic candidate LAB strains. This shows that P. terebinthus hexane extract at appropriate concentrations can be used together with probiotic strains as a natural preservative and biopreservative to prevent food spoilage and extend shelf life. [ABSTRACT FROM AUTHOR]

With the development and progress of human society and the continuous enhancement of people's health awareness, lactic acid bacteria inhibitors as a natural biopreservative have an irreplaceable position, with the advantages of high efficiency, broad spectrum, stability, safety and other characteristics. This paper studied the antibacterial effect of 23 lactic acid bacteria; the strains with the best antibacterial effect was identified by 16S rDNA method as being Lactobacillus rhamnosus L57 and was applied to banana storage. Our study showed that Lactobacillus rhamnosus L57 has a broad spectrum, inhibiting Escherichia coli, Staphylococcus aureus, Vibrio alginolyticus and Bacillus nato. Excluding the interference of organic acids, hydrogen peroxide and extracellular polysaccharide, the salting out of ammonium sulfate preliminarily determined that the proteins or peptides are the antibacterial substances in the antibacterial agent. Physicochemical properties showed that the microorganism had good antibacterial activity after trypsin, pepsin and papain, with good tolerance to pH, temperature and UV light, and the pH optimal range of 2.0-4.0. The mixture of freeze-dried powder of L. rhamnosus L57, chitosan and natamycin was used for banana preservation, with the proportion of freeze-dried powder of 1.25%, chitosan 1.5% and natamycin 0.03%. The preservation period was extended by 4 days compared with the absence of either bacteriostatic agent.

This study presents an innovative approach to enhancing the shelf life and maintaining the quality of sliced cooked ham through the application of a natural biopreservative derived from lactic fermentation. The biopreservative, at concentrations ranging from 1% to 3.5%, demonstrated substantial efficacy in microbial inhibition, keeping the microbial density low and relatively constant over time (p < 0.05). Remarkably, even at the lower concentration of 1%, the microbial growth rates were significantly reduced, with the treated samples showing notable stability over 24 days at both 7 °C and 25 °C. The microbial count in the treated with biopreservative group was significantly lower (3.19 log cfu/g) compared to the blank (4.59 log cfu/g) and control (5.01 log cfu/g) over 4 days at 7 °C. The shelf life of the ham was 24 days for the blank, 20 days for the control, and 101 days for the treated group at 7 °C. Moreover, colorimetric analysis revealed that the treated samples maintained better color stability, experiencing less variation in the hue angle and chroma, suggesting a protective effect against quality degradation over time. The successful application of the biopreservative aligns with the growing consumer demand for natural food additives and underscores the movement toward sustainable, health-conscious food preservation practices. The findings of this study indicate a promising avenue for the food industry to adopt environmentally friendly alternatives to synthetic additives, which could significantly influence future standards in food processing and preservation.

Fresh-cut vegetables are widely consumed, but there is no food preservative available to selectively inhibit vancomycin-resistant E. faecalis, which is a serious health menace in fresh-cut vegetables. To develop a promising food biopreservative, a bacteriocin, paracin wx7, was synthesized, showing selective inhibition against E. faecalis with MIC values of 4–8 μM. It showed instant bactericidal mode within 1 h at high concentrations with concomitant cell lysis against vancomycin-resistant E. faecalis. Its lethal effect was visualized in a dose-dependent manner by PI/SYTO9 staining observation. The results of an in vivo control experiment carried out on E. faecalis in fresh-cut lettuce showed that 99.97% of vancomycin-resistant E. faecalis were dead after 64 μM paracin wx7 treatment for 7 days without influencing total bacteria. Further, the action mechanism of paracin wx7 was investigated. Confocal microscopy showed that paracin wx7 was located both on the cell envelope and in cytoplasm. For the cell envelope, the studies of membrane permeability using SYTOX Green dyeing and DNA leakage revealed that paracin wx7 damaged the membrane integrity of E. faecalis. Simultaneously, it exhibited membrane depolarization after analysis using DiSC3(5). Damage to the cell envelope resulted in cell deformation observed by scanning electron microscopy. On entering the cytoplasm, the paracin wx7 induced the production of endogenous reactive oxygen species.

Introduction:Listeria monocytogenes is an opportunistic foodborne pathogen that can cause death to infected humans. The bacterial pathogen was frequently associated with food-borne origins including seafood. Thus, the present study aimed at screening anti-listeria-producing lactic acid bacteria (AL-LAB) isolated from the intestinal tracts of wild gilt-head seabream (Sparus aurata).

In the present study, the chemical composition and the in vitro antimicrobial and antibiofilm activity of an ethanolic extract of propolis (EEP) from Tunisia against different ATCC and wild bacterial strains were evaluated. In situ antimicrobial activity and sensory influence of different EEP concentrations (0.5% and 1%), also in combination with 1% vinegar, were evaluated in chilled vacuum-packed salmon tartare. Furthermore, a challenge test was performed on salmon tartare experimentally contaminated with Listeria monocytogenes and treated with the different EEP formulations. The in vitro antimicrobial and antibiofilm activity was observed only against Gram-positive bacteria, such as L. monocytogenes and S. aureus, both ATCC and wild. Results of the in situ analyses revealed significant antimicrobial activity against aerobic colonies, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp. only when the EEP was used at 1% and in combination with 1% vinegar. The 1% EEP in combination with 1% vinegar was the most effective treatment also against L. monocytogenes, although 0.5% and 1% EEP used alone also showed antilisterial effects. After 7 days of storage, the sensory influence on odor, taste and color of salmon tartare was negligible for all EEP formulations. In this background, results obtained confirmed the antimicrobial efficacy of propolis which could be proposed as a suitable biopreservative to ensure safety and improve the quality of food. [ABSTRACT FROM AUTHOR]

Abstract Background Due to the detrimental effects of chemical preservatives, there has been an increasing demand for safer, healthier and natural bio-preservatives. Bacteriocins have attracted increasing interest because of their potential as natural bio-preservatives. Results We screened a large number of Bacillus thuringiensis strains and isolated one strain (B. thuringiensis P86) with antimicrobial activity against several foodborne pathogens. Three novel leaderless bacteriocins, including thucin A1, thucin A2 and thucin A3, were purified and identified from the culture supernatant of B. thuringiensis P86, whose molecular masses were 5552.02, 5578.07 and 5609.06 Da, respectively. Thucin A1 was then selected as a representative to be tested, and it exhibited potent inhibitory activity against all tested gram-positive bacteria. More importantly, thucin A1 showed stronger antimicrobial activity than nisin A against two important foodborne pathogens Bacillus cereus and Listeria monocytogenes. In addition, thucin A1 exhibited strong acid–base adaptability (pH 2–11), high endurance to heat, good stability to trypsin and pepsin, no hemolysis activity and cytotoxicity, and could effectively inhibit or eliminate Bacillus cereus and Listeria monocytogenes in skim milk. Conclusions Our findings indicate that these novel leaderless bacteriocins are potentially promising food biopreservatives.

The fermentation process results in the presence of lactic acid bacteria (LAB). Traditional fermented buffalo milk from the Indonesian province of West Sumatra is known as dadih. Bacteriocins are naturally occurring antimicrobial peptides that can be produced by LAB. These bacteriocins have the potential to be used as natural preservatives. This research was conducted with the intention of isolating and partially characterizing a bacteriocin that was generated by Lactobacillus pentosus 124-2 that was isolated from dadih. Using MRS agar media and 16sRNA, the LAB that was found in dadih was successfully isolated. Bacteriocins were produced using media consisting of MRS broth. After the bacteriocins were obtained, they were subjected to a series of purification processes, one of which included ammonium sulfate (70%) followed by gel filtration chromatography for additional purification. According to the findings, the strain of LAB that was discovered in the dadih was Lactobacillus pentosus 124-2. The specific activity of the bacteriocins rose, allowing for the effective completion of the purification process. The pure bacteriocins had the greatest specific activity values, at 60.59 AU/mg, while the yield values were 0.41% and 3.15-fold. Bacteriocins in their purest form were able to inhibit the growth of Salmonella species as well as Staphylococcus aureus. The characterization results included partial bacteriocins that were resistant to pH 2, 4, and 6; antibacterial activity that was was stable at a temperature range of 25 °C to 121 °C; and resistance to the addition of 2%, 4%, and 6% salt concentrations. Microbial stability against the addition of surfactants EDTA, SDS, and Tween 80 was also obtained. In light of these findings, a bacteriocin derived from L. pentosus possesses the possible ability to be utilized in the food business as a biopreservative. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) are economically important because of their fermentative aptitude and they also confer health and nutritional benefits. Pediococcus acidilactici NCDC 252 (NCDC 252) is potential probiotic with novel genome that exhibited all in-vitro probiotic attributes, colonization in intestine and survival in conditions that mimick gastric, intestinal and vaginal fluid. Genome was screened for its ability to produce antimicrobial peptide (AMP). AMP from NCDC 252 was isolated and purified against indicator strain (Escherichia coli). AMP production was optimized in MRS broth at 32 °C, pH 6 and upto 36 h of incubation under both aerobic and anaerobic conditions. AMP was purified 2.2 fold with yield of 7.2% and specific activity of 64.5 U mg/mL using ammonium sulphate precipitation (upto 70%) and gel filtration chromatography. Molecular weight of purified AMP was calculated to be 2.5 KDa. Tricine SDS-PAGE and LC/MS studies confirmed it to be a low molecular weight peptide. AMP was stable over pH range of 3 to 9 and temperature range of 40 °C to 100 °C. Enzymatic treatment inactivated the AMP whereas, detergent treatment enhanced its activity. Biopreservation potential of purified AMP and whole NCDC 252 cells was studied by incubating them with some dairy products, apple juice, apricot pulp and pre-pasteurized wine over 72 h. Bacterial growth in AMP treated food products reduced significantly after 72 h. Viable cell count decreased to approximately half in both purified AMP treated and NCDC 252 treated food products. Purified AMP demonstrated exceptional resistance to heat treatment over a wide pH range, enabling it to establish itself as a biopreservative. Studies on biopreservation potential revealed NCDC 252 derived AMP to be effective even at low concentrations and it can be utilised to extend the shelf life of food goods. [ABSTRACT FROM AUTHOR]

Despite the fact that researchers have been working on the preservation of raw milk at room temperature for several decades, most of the processes are limited to the use of chemical preservatives. One of the major problems of raw milk self-life is its spoilage at ambient temperature during the summer season. Therefore, in the present study, research has been conducted to control raw milk spoilage at 4 °C and 35 °C (considered in different regions' ambient temperatures). ε-Polylysine, a natural preservative approved for food use, was isolated from the fermentation broth of Bacillus licheniformis PL26 grown in an M3G medium, and its antimicrobial preservation properties for milk applications were tested. The raw milk samples containing 0.02% w/v ε-polylysine could be stored at 4 °C for up to 16 days without spoilage, however, raw milk samples without ε-polylysine as preservative spoiled on the 8th day even at 4 °C refrigeration conditions. Raw milk containing 0.02% ε-polylysine in combination with 0.2% sodium bicarbonate (added to avoid acidification) could be stored at ambient temperature (35 °C) for up to 48 h. The changes in milk composition, especially of the casein, lactose, and fat stability, during storage under different conditions with/without ε-polylysine, were studied as well. The present study proves that ε-polylysine can be successfully used as a new biopreservative. Therefore, for the dairy industry, a natural preservative to store milk at room temperature during the summer season, replacing synthetic preservatives derived from renewable sources, can be proposed. Once again, marine bacteria seem to be one of the promising sustainable and renewable sources of biologically active compounds such as new food biopreservatives [ABSTRACT FROM AUTHOR]

Background: Due to the detrimental effects of chemical preservatives, there has been an increasing demand for safer, healthier and natural bio-preservatives. Bacteriocins have attracted increasing interest because of their potential as natural bio-preservatives. Results: We screened a large number of Bacillus thuringiensis strains and isolated one strain (B. thuringiensis P86) with antimicrobial activity against several foodborne pathogens. Three novel leaderless bacteriocins, including thucin A1, thucin A2 and thucin A3, were purified and identified from the culture supernatant of B. thuringiensis P86, whose molecular masses were 5552.02, 5578.07 and 5609.06 Da, respectively. Thucin A1 was then selected as a representative to be tested, and it exhibited potent inhibitory activity against all tested gram-positive bacteria. More importantly, thucin A1 showed stronger antimicrobial activity than nisin A against two important foodborne pathogens Bacillus cereus and Listeria monocytogenes. In addition, thucin A1 exhibited strong acid–base adaptability (pH 2–11), high endurance to heat, good stability to trypsin and pepsin, no hemolysis activity and cytotoxicity, and could effectively inhibit or eliminate Bacillus cereus and Listeria monocytogenes in skim milk. Conclusions: Our findings indicate that these novel leaderless bacteriocins are potentially promising food biopreservatives. [ABSTRACT FROM AUTHOR]

Bacteriocins are a diverse group of ribosomally synthesised antimicrobial peptides/proteins that play an important role in self-defence. They are widely used as bio-preservatives and effective substitutes for disease eradication. They can be used in conjunction with or as an alternative to antibiotics to minimize the risk of resistance development. There are remarkably few reports indicating resistance to bacteriocins. Although there are many research reports that emphasise heterologous expression of bacteriocin, there are no convincing reports on the significant role that intrinsic and extrinsic factors play in overexpression. A coordinated and cooperative expression system works in concert with multiple genetic elements encoding native proteins, immunoproteins, exporters, transporters and enzymes involved in the post-translational modification of bacteriocins. The simplest way could be to utilise the existing E. coli expression system, which is conventional, widely used for heterologous expression and has been further extended for bacteriocin expression. In this article, we will review the intrinsic and extrinsic factors, advantages, disadvantages and major problems associated with bacteriocin overexpression in E. coli. Finally, we recommend the most effective strategies as well as numerous bacteriocin expression systems from E. coli, Lactococcus, Kluveromyces lactis, Saccharomyces cerevisiae and Pichia pastoris for their suitability for successful overexpression. • Bacteriocins are proteins or peptides synthesised by one strain and antagonistic to others strain. • They have been extensively used as biopreservatives and play a significant role in food safety. • The source microbes are known to produce very scant amounts that are not sufficient for the food industry. • The critical issues of heterologous expression, such as intrinsic and extrinsic factors, have been discussed. • Finally discussed were at the end we disscussed various hosts and the genetic systems that may be followed for overexpression, leading to food and biomedical applications. [ABSTRACT FROM AUTHOR]

The multiple bacteriocins produced by Lactiplantibacillus plantarum PUK6 isolated from misozuke-tofu (tofu pickled in miso) were identified as plantaricins A, EF, and NC8. The pln locus (21,847 bp) containing the three plantaricin structural genes and another newly found putative bacteriocin structural genes (orf1 and orf2) were determined, and a biosynthesis mechanism was proposed. Reverse transcription-PCR analysis revealed that orf1 and orf2 , the putative two-peptide bacteriocin structural genes, were expressed after 8 h (logarithmic growth phase) and 20 h (stationary growth phase) of cultivation of the PUK6 strain. Additionally, the growth inhibition profile obtained using the chemically synthesized mature peptides of Orf1 and Orf2 (referred to as mOrf1 and mOrf2) showed that the equimolar mixture of mOrf1 and mOrf2 exhibited bactericidal effect against the indicator strain Latilactobacillus sakei subsp. sakei JCM 1157T. Furthermore, fluorescence microscopic analysis revealed disruption of the cell membranes. These findings indicate that orf1 and orf2 are structural genes encoding class IIb bacteriocins consisting of two peptides. Therefore, the novel bacteriocin encoded by plnPUK6α (orf1) and plnPUK6β (orf2) genes was named plantaricin PUK6. Since the PUK6 strain produces multiple bacteriocins, when used as a starter culture, it could contribute to improving the shelf life of fermented foods and preventing the appearance of bacteriocin-resistant bacteria. [ABSTRACT FROM AUTHOR]

The increased resistance of bacteria to antimicrobials, as well as the growing interest in innovative and sustainable alternatives to traditional food additives, are driving research towards the use of natural food preservatives. Among these, hydrolates (HYs) have gained attention as "mild" alternatives to conventional antimicrobial compounds. In this study, the response of L. monocytogenes ATCC 7644 exposed to increasing concentrations of Coridothymus capitatus HY (CHY) for 1 h at 37 °C was evaluated by means of Phenotype Microarray, modelling the kinetic data obtained by inoculating control and treated cells into GEN III microplates, after CHY removal. The results revealed differences concerning the growth dynamics in environmental conditions commonly encountered in food processing environments (different carbon sources, pH 6.0, pH 5.0, 1–8% NaCl). More specifically, for treated cells, the lag phase was extended, the growth rate was slowed down and, in most cases, the maximum concentration was diminished, suggesting the persistence of stress even after CHY removal. Confocal Laser Scanner Microscopy evidenced a diffuse aggregation and suffering of the treated cells, as a response to the stress encountered. In conclusion, the treatment with HY caused a stressing effect that persisted after its removal. The results suggest the potential of CHY application to control L. monocytogenes in food environments. [ABSTRACT FROM AUTHOR]

Abstract Background Pediococcus pentosaceus, a promising strain of lactic acid bacteria (LAB), is gradually attracting attention, leading to a rapid increase in experimental research. Due to increased demand for practical applications of microbes, the functional and harmless P. pentosaceus might be a worthwhile LAB strain for both the food industry and biological applications. Results As an additive, P. pentosaceus improves the taste and nutrition of food, as well as the storage of animal products. Moreover, the antimicrobial abilities of Pediococcus strains are being highlighted. Evidence suggests that bacteriocins or bacteriocin-like substances (BLISs) produced by P. pentosaceus play effective antibacterial roles in the microbial ecosystem. In addition, various strains of P. pentosaceus have been highlighted for probiotic use due to their anti-inflammation, anticancer, antioxidant, detoxification, and lipid-lowering abilities. Conclusions Therefore, it is necessary to continue studying P. pentosaceus for further use. Thorough study of several P. pentosaceus strains should clarify the benefits and drawbacks in the future.

In this study, the clove essential oil-loaded nanoemulsion system was prepared using corn and soybean oils as a coating agent for refrigerated chicken fillets, and its bio preservative properties were investigated during 15 days at 4 °C. A total of 6 compounds were identified from the clove essential oil, with the dominant compounds being eugenol (88.38%) and beta-caryophyllene (6.01%). The coating process led to the reduction of titratable acidity of the chicken fillets during the storage time. Compared to non-coated samples, nanoemulsion-treated samples presented less increase in peroxide value (from 0.057 to 0.089) and thiobarbituric acid (from 0.234 to 0.835) values along the storage time. Increasing the content of clove essential oil in the nanoemulsions resulted in a significant reduction in total volatile basic nitrogen content. The coating process was highly effective in decreasing the total viable count, and psychrophilic bacteria growth, while antimicrobial activity varied depending on the nanoemulsion formulation and storage time. Using the nanoemulsions containing 1% clove essential oil led to a significant increase in sensory parameter scores. Therefore, the treatment containing 1% clove essential oil due to the highest acceptability score was chosen as the best treatment. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to determine the effect of the bacteriocin produced by strain 9 lactic acid bacteria (LAB) isolate on the biopreservation of beef. Materials and Methods: The strain 9 LAB isolate was identified conventionally by culturing with de Man, Rogosa, and Sharpe broth medium followed by Gram staining and catalase testing. The molecular confirmation of the isolate involved analyzing the 16S rRNA gene with specific primers, that is, B27F (5-AGAGTTTGATCCTGGCTCAG-3) and U1492R (5-GGTTACCTTGTTACGACTT-3). Then, the isolate was centrifuged to evaluate the bacteriocin production, and the effect of the biopreservative activity in beef was evaluated by measuring the NH3 produced with the Eber test and the organoleptic acceptance from expert panels. Results: This study confirmed that the strain 9 LAB isolate was a strain of Pediococcus pentosaceus, and the bacteriocin product showed biopreservative potential. The biopreservative potential was characterized by a significant decline in the production of NH3 and the panel's acceptance of the texture and tenderness of the beef, compared with the control, after 10 days of constant treatment. Conclusion: This study highlighted the high biopreservative potency of pediocin produced by P. pentosaceus strain 9. This was noted by the production of NH3 and the modifications in texture and tenderness.

In the present study, the chemical composition and the in vitro antimicrobial and antibiofilm activity of an ethanolic extract of propolis (EEP) from Tunisia against different ATCC and wild bacterial strains were evaluated. In situ antimicrobial activity and sensory influence of different EEP concentrations (0.5% and 1%), also in combination with 1% vinegar, were evaluated in chilled vacuum-packed salmon tartare. Furthermore, a challenge test was performed on salmon tartare experimentally contaminated with Listeria monocytogenes and treated with the different EEP formulations. The in vitro antimicrobial and antibiofilm activity was observed only against Gram-positive bacteria, such as L. monocytogenes and S. aureus, both ATCC and wild. Results of the in situ analyses revealed significant antimicrobial activity against aerobic colonies, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp. only when the EEP was used at 1% and in combination with 1% vinegar. The 1% EEP in combination with 1% vinegar was the most effective treatment also against L. monocytogenes, although 0.5% and 1% EEP used alone also showed antilisterial effects. After 7 days of storage, the sensory influence on odor, taste and color of salmon tartare was negligible for all EEP formulations. In this background, results obtained confirmed the antimicrobial efficacy of propolis which could be proposed as a suitable biopreservative to ensure safety and improve the quality of food.

The fermentation process results in the presence of lactic acid bacteria (LAB). Traditional fermented buffalo milk from the Indonesian province of West Sumatra is known as dadih. Bacteriocins are naturally occurring antimicrobial peptides that can be produced by LAB. These bacteriocins have the potential to be used as natural preservatives. This research was conducted with the intention of isolating and partially characterizing a bacteriocin that was generated by Lactobacillus pentosus 124-2 that was isolated from dadih. Using MRS agar media and 16sRNA, the LAB that was found in dadih was successfully isolated. Bacteriocins were produced using media consisting of MRS broth. After the bacteriocins were obtained, they were subjected to a series of purification processes, one of which included ammonium sulfate (70%) followed by gel filtration chromatography for additional purification. According to the findings, the strain of LAB that was discovered in the dadih was Lactobacillus pentosus 124-2. The specific activity of the bacteriocins rose, allowing for the effective completion of the purification process. The pure bacteriocins had the greatest specific activity values, at 60.59 AU/mg, while the yield values were 0.41% and 3.15-fold. Bacteriocins in their purest form were able to inhibit the growth of Salmonella species as well as Staphylococcus aureus. The characterization results included partial bacteriocins that were resistant to pH 2, 4, and 6; antibacterial activity that was was stable at a temperature range of 25 °C to 121 °C; and resistance to the addition of 2%, 4%, and 6% salt concentrations. Microbial stability against the addition of surfactants EDTA, SDS, and Tween 80 was also obtained. In light of these findings, a bacteriocin derived from L. pentosus possesses the possible ability to be utilized in the food business as a biopreservative.

Cocoa Pod Husks (CPH) and by-product from supercritical CO2 extracted Rosa damascena Mill. (RDCO2) were used as biopreservatives in muffins. Both by-products were rich source of polyphenols: 28.3 ± 0.6 mg/g Dry Weight (DW) and 17.9 ± 0.7 mg/g DW RDCO2 and CPH, respectively, and exhibited potent antioxidant capacity: 449.1 ± 8.5 μmol Trolox Equivalents (TE)/g DW (by ORAC method) and 58.9 ± 2.1 μmol Gallic Acid Equivalents (GAE)/g DW (by HORAC method) for the RDCO2, and 373.8 ± 9.0 μmol TE/g DW (by ORAC) and 36.8 ± 3.8 μmol GAE/g DW (by HORAC) for the CPH. RDCO2 extracts successfully inhibited development of several important pathogenic and saprophytic microorganisms causing microbial spoilage of food systems. The control muffins were good for consumption up to the 17th day, while the products supplemented with RDCO2 and CPH: until 20th day of storage at 22 ± 0.5 °C. The amount of dietary fibers in muffins supplemented with both by-products increased 3 times (8.57 ± 0.12 %) compared to control (2.91 ± 0.12 %) and the polyphenolic compounds increased 2.5 times (from 50.0 ± 0.3 for the control to 185.9 ± 0.6 mg/g DW). For the first time by-product of supercritical CO2 extraction of Rosa damascena Mill. was characterized and used as natural and cheap biopreservative. [ABSTRACT FROM AUTHOR]

The biopreservation strategy allows extending the shelf life and food safety through the use of indigenous or controlled microbiota and their antimicrobial compounds. The aim of this work was to characterize an inhibitory substance with bacteriocin-like activity (Sak-59) produced by the potentially probiotic L. sakei strain from artisanal traditional Kazakh horse meat product Kazy. The maximum production of Sak-59 occurred at the stationary phase of the L. sakei growth. Sak-59 showed inhibitory activity against gram-positive meat spoilage bacteria strains of Listeria monocytogenes, Staphylococcus aureus, and pathogenic gram-negative bacteria strains of Serratia marcescens and Escherichia coli, but not against the tested Lactobacilli strains. Sak-59 activity, as measured by diffusion assay in agar wells, was completely suppressed after treatment with proteolytic enzymes and remained stable after treatment with α-amylase and lipase, indicating that Sak-59 is a peptide and most likely not glycosylated or lipidated. It was concluded that Sak-59 is a potential new bacteriocin with a characteristic activity spectrum, which can be useful in the food and feed industries. [ABSTRACT FROM AUTHOR]

During the cultivation and harvesting of fruit and vegetables, a large number of microorganisms accumulate on their surface. Their active and excessive reproduction leads to spoilage of products. The purpose of the study was to assess the effect of combining various packaging technologies with different biopreservatives on the stability of physicochemical and microbiological characteristics of fresh vegetables and fruit during storage. Samples of fruit and vegetable products (apples, tomatoes) were subjected to the following procedures: packaging without treatment, treatment with a mixture of bacteriocin-like substances and packaging with or without modified atmosphere. Packaged samples were stored in a refrigerator at a temperature of 4°C for 25 days. The bacteriocin-like substances in combination with modified atmosphere reduced the contamination of samples by pathogenic microorganisms at least 4 times while maintaining the quality characteristics of the fruit during the storage period. A biopreservative in combination with modified atmosphere can be used to control microbial spoilage and to keep fruit and vegetables fresh after harvest.

In this experimental study, the effect of pH (2, 4, 11), temperature (4, 85, 121 oC) and bile salt (0.3, 0.6, 1%) treatments on inhibitory potential of cell-free supernatant (CFS) obtained from barley sourdough dominant LAB (Pediococcus stilesii, Weissella cibaria, Lactobacillus brevis and Lactobacillus curieae) isolates, against B. subtilis were investigated based on microdilution method in comparison to untreated CFS. The safety of LAB isolates was also assessed by control of changes in serum parameters and liver enzymes in mice fed with them. Results were analyzed by one-way analysis of variance. Based on results, LAB CFS had antagonistic activity against B. subtilis. Inhibitory effects of the CFS under pH and temperature treatments were decreased, but under bile salt treatment was increased. Changes in serum parameters and liver enzymes in mice fed with LAB isolates were also in normal ranges and so on, safety of the LAB isolates was approved. By considering the antagonistic activity of LAB CFS under pH, temperature and salt treatments, against B. subtilis it is possible to use from the CFS as a biopreservative in food processing chain.

Exopolysaccharides (EPSs) are metabolites synthesized and excreted by a variety of microorganisms, including lactic acid bacteria (LAB). EPS serve several biological functions such as interactions between bacteria and their environments, protection against hostile conditions including dehydration, the alleviation of the action of toxic compounds (bile salts, hydrolyzing enzymes, lysozyme, gastric, and pancreatic enzymes, metal ions, antibiotics), and stresses (changing pH, osmolarity), and evasion of the immune response and phage attack. Bacterial EPSs are considered valuable by the food, pharmaceutical, and nutraceutical industries, owing to their health-promoting benefits and rheological impacts. Numerous studies have reported the unusual antimicrobial activities of various EPS against a wide variety of pathogenic microbes (bacteria, virus, and fungi). This review aims to provide a comprehensive examination of the in vitro and in vivo antimicrobial activities of different EPSs, mainly against foodborne bacterial, fungal, and viral pathogens. The mechanism of EPS action against these pathogens as well as the methods used to measure antimicrobial activities are critically reviewed.

The adverse effects of chemical preservatives used to prevent food spoilage have led to the search for various biopreservatives. Considering this, a study was undertaken to prepare crude extract (CE) from Indian curd (a fermented dairy product) and characterized it in terms of antioxidant and antimicrobial activities against some common food-borne bacteria. The CE exhibited well pronounced antimicrobial activity against Bacillus cereus and Salmonella typhimurium. The minimum inhibitory concentration (MIC) of CE was recorded for 2-fold concentrated solution prepared from a 10-fold stock. The CE exhibited a significantly higher (p < 0.05) antioxidant and antimicrobial activities compared to its fractions. The CE was found to be heat stable (up to 100 ℃ for 30 min) and exhibited a significant (p < 0.05) increase in activity at pH 2–7 and in combination with 2% citric acid solution. Trypsin treatment suggested it to be of proteinaceous in nature. The antibacterial activity of CE remained intact at 4 ℃ for seven days, whereas non-significant (p > 0.05) changes in its activity were noted during storage at −20 ℃ for 30 days. The curd sample used for preparation of CE, when tested for bacteriocin production and subsequent antimicrobial activity, did not show inhibition against S. typhimurium. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis of CE and its fractions revealed multi-banding pattern. By virtue of its bioactivities observed, CE can be explored as a promising food biopreservative. [ABSTRACT FROM AUTHOR]

Exopolysaccharides (EPSs) are metabolites synthesized and excreted by a variety of microorganisms, including lactic acid bacteria (LAB). EPS serve several biological functions such as interactions between bacteria and their environments, protection against hostile conditions including dehydration, the alleviation of the action of toxic compounds (bile salts, hydrolyzing enzymes, lysozyme, gastric, and pancreatic enzymes, metal ions, antibiotics), and stresses (changing pH, osmolarity), and evasion of the immune response and phage attack. Bacterial EPSs are considered valuable by the food, pharmaceutical, and nutraceutical industries, owing to their health-promoting benefits and rheological impacts. Numerous studies have reported the unusual antimicrobial activities of various EPS against a wide variety of pathogenic microbes (bacteria, virus, and fungi). This review aims to provide a comprehensive examination of the in vitro and in vivo antimicrobial activities of different EPSs, mainly against foodborne bacterial, fungal, and viral pathogens. The mechanism of EPS action against these pathogens as well as the methods used to measure antimicrobial activities are critically reviewed. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a widespread foodborne pathogen that threatens human health. In particular, multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) are emerging problems in modern health care, food safety, and animal health, which require the development of new antimicrobials to replace overused conventional antibiotics. Dairy products can potentially act as vehicles for the transmission of S. aureus and other antibiotic-resistant strains from the farm into the general human population, and should be controlled during the production and storage process. Recently, bacteriophage endolysins, which degrade the cell wall that is indispensable for bacteria, have been deemed promising antimicrobial agents. In this study, one endolysin, LysGH15, demonstrated prominent antimicrobial efficacy against S. aureus , as did its catalytic domain, cysteine, histidine-dependent amidohydrolase/peptidases (CHAP) LysGH15 alone. The LysGH15 and CHAP LysGH15 exhibited different characteristics in one MRSA strain (MRSA 2701), reaching the highest activity under different conditions (35°C and pH 6.0 for LysGH15, 40°C and pH 9.0 for CHAP LysGH15). A difference in the sensitivity of LysGH15 and CHAP LysGH15 to NaCl concentration was found, where the lytic activity of LysGH15 depends strongly on its binding domain's binding capacity, which is positively correlated with the NaCl concentration, whereas the CHAP LysGH15 activity showed a negative correlation with the NaCl concentration. When the NaCl concentration was 450 m M , the lytic activity of LysGH15 reached its peak, whereas the lytic activity of CHAP LysGH15 was the highest in the absence of NaCl. The difference in NaCl sensitivity between LysGH15 and CHAP LysGH15 may be due to the sensitivity of the SH3b binding protein of LysGH15 to NaCl. The CHAP LysGH15 was tested as a biopreservative in whole and skim milk and exerted effective control against S. aureus (declined by approximately 2.5 log 10 cfu/mL when incubated at 4°C for 8 h), which suggests promise for application in dairy products. [ABSTRACT FROM AUTHOR]

Background: Pediococcus pentosaceus, a promising strain of lactic acid bacteria (LAB), is gradually attracting attention, leading to a rapid increase in experimental research. Due to increased demand for practical applications of microbes, the functional and harmless P. pentosaceus might be a worthwhile LAB strain for both the food industry and biological applications. Results: As an additive, P. pentosaceus improves the taste and nutrition of food, as well as the storage of animal products. Moreover, the antimicrobial abilities of Pediococcus strains are being highlighted. Evidence suggests that bacteriocins or bacteriocin-like substances (BLISs) produced by P. pentosaceus play effective antibacterial roles in the microbial ecosystem. In addition, various strains of P. pentosaceus have been highlighted for probiotic use due to their anti-inflammation, anticancer, antioxidant, detoxification, and lipid-lowering abilities. Conclusions: Therefore, it is necessary to continue studying P. pentosaceus for further use. Thorough study of several P. pentosaceus strains should clarify the benefits and drawbacks in the future. [ABSTRACT FROM AUTHOR]

The increased resistance of bacteria to antimicrobials, as well as the growing interest in innovative and sustainable alternatives to traditional food additives, are driving research towards the use of natural food preservatives. Among these, hydrolates (HYs) have gained attention as “mild” alternatives to conventional antimicrobial compounds. In this study, the response of L. monocytogenes ATCC 7644 exposed to increasing concentrations of Coridothymus capitatus HY (CHY) for 1 h at 37 °C was evaluated by means of Phenotype Microarray, modelling the kinetic data obtained by inoculating control and treated cells into GEN III microplates, after CHY removal. The results revealed differences concerning the growth dynamics in environmental conditions commonly encountered in food processing environments (different carbon sources, pH 6.0, pH 5.0, 1–8% NaCl). More specifically, for treated cells, the lag phase was extended, the growth rate was slowed down and, in most cases, the maximum concentration was diminished, suggesting the persistence of stress even after CHY removal. Confocal Laser Scanner Microscopy evidenced a diffuse aggregation and suffering of the treated cells, as a response to the stress encountered. In conclusion, the treatment with HY caused a stressing effect that persisted after its removal. The results suggest the potential of CHY application to control L. monocytogenes in food environments.

In this study, we evaluated the efficacy of 3 commercial protective cultures designated PC1 (Lactobacillus spp.), PC2 (Lactobacillus rhamnosus) , and PC3 (Lactobacillus rhamnosus) as biopreservatives in queso fresco (QF) against 9 yeast strains (Candida zeylanoides , Clavispora lusitaniae , Debaryomyces hansenii , Debaryomyces prosopidis , Kluyveromyces marxianus , Meyerozyma guilliermondii , Pichia fermentans , Rhodotorula mucilaginosa , and Torulaspora delbrueckii) and 11 mold strains (Aspergillus cibarius , Aureobasidium pullulans , Penicillium chrysogenum , Penicillium citrinum , Penicillium commune , Penicillium decumbens , Penicillium roqueforti , Mucor genevensis , Mucor racemosus , Phoma dimorpha , and Trichoderma amazonicum). All fungal spoilage strains were previously isolated from dairy processing environments. A positive control (C) with no protective culture was included. Fungal spoilage organisms were inoculated on cheese surfaces at an inoculum level of 20 cfu/g, and cheeses were stored at 6 ± 2°C throughout the study. For yeast enumeration, cheeses were sampled on d 0, 7, 14, and 21 postinoculation. Significant inhibition was detected for each yeast strain by comparing yeast counts for each cheese treated with protective culture against the control cheese using one-way ANOVA with Bonferroni correction performed individually at d 7, 14, and 21 postinoculation. Mold growth was visually observed and imaged weekly through 70 d postinoculation. Whereas PC3 inhibited Cl. lusitaniae , Mey. guilliermondii , and Ph. dimorpha , PC2 inhibited the outgrowth of Cl. lusitaniae , D. hansenii , and Ph. dimorpha. Protective culture 1 had the broadest spectrum of efficacy across yeast and molds, delaying spoilage caused by 4 distinct yeast strains (Cl. lusitaniae , D. hansenii , D. prosopidis , and Mey. guilliermondii), and inhibiting visible growth of 2 mold strains (P. chrysogenum and Ph. dimorpha). Results demonstrated that commercial protective cultures vary in performance, as indicated by the breadth of mold and yeast inhibition at both the genus and species level. This study suggests that manufacturers looking into using protective cultures should investigate their efficacy against specific fungal strains of concern. [ABSTRACT FROM AUTHOR]

In the present investigation the biopreservative effect of bacteriocin of Brevibacillus laterosporus TK3 was investigated in raw chicken. Bacteriocin producing strain has been isolated from "Tatwakhar"- a flour prepared from seeds of Indian Horse Chestnut (Aesculus indica). Bacteriocin of Brevibacillus laterosporus TK3 showed strong antagonism against food spoilage/pathogenic bacteria viz. Listeria monocytogenes and Staphylococcus aureus. The bacteriocin was purified and molecular weight of this novel bacteriocin was found to be 6 kDa. This purified bacteriocin with specific activity 34,482.0 AU/mg was applied in raw chicken and minced chicken against L. monocytogenes and S. aureus which showed the positive results in controlling the growth of these deadly pathogens. Purified bacteriocin was found successful in controlling the growth of L. monocytogenes up to 7th day which is almost at par with the results achieved with chemical preservative i.e. sodium nitrite. Further, purified bacteriocin restricted the growth of S. aureus up to 5th day whereas chemical preservative was able to control the growth of S. aureus up to 3rd day. The results found in these experiments deal with application of bacteriocin as biopreservative in chicken as an alternative to chemical preservative are quite encouraging and satisfactory. [ABSTRACT FROM AUTHOR]

This study evaluated the preserving effect of Davidson's plum (Davidsonia pruriens) fruit powder (DPP) in raw beef patties. Minced meat patties were treated with no additive (negative control), 45 mg/hg of Sodium metabisulphite (SMB), or DPP (0.2, 0.4, 0.6 and 0.8 g/hg) and stored for 20 days at 4 ± 1 °C. Lipid oxidation, microbial growth rate, pH, instrumental color were studied. Bioactive compounds of the DPP were analysed using UHPLC–HRAM-Orbitrap-MS/MS. The results showed that DPP contained high concentration of both anthocyanins and non-anthocyanins compounds. Furthermore, the beef patties treated with DPP exhibited reduced lipid oxidation (p <0.05) in comparison to beef patties with no added preservative. Moreover, the addition of DPP at concentration equal to or greater than 0.2 g/hg slowed down microbial growth (p <0.05) compared to raw beef patties with no preservative added. However, SMB-treated samples had the greatest antimicrobial activities in comparison to all other treatments. The inclusion of DPP led to reduced redness and pH of treated raw beef patties. This study provides evidence that Davidson's plum fruit can be used as natural preservative in raw processed meat. • The effectiveness of Davidson's plum powder (DPP) as natural preservative in raw beef patties was evaluated. • DPP had greater antimicrobial and antioxidant effects compared to both Sodium metabisulphite and the negative control. • The inclusion of the DPP impacted the redness of the raw beef patty. • The inclusion of the DPP in the raw beef patty may be used as a biopreservative. [ABSTRACT FROM AUTHOR]

In this study, strains of lactic acid bacteria capable of bacteriocin production were isolated from Lighvan cheese samples obtained from East Azerbaijan, Iran. Among 16 isolates initially identified as Lactococcus lactis, four isolates were phenotipically determined as bacteriocinogenic. The isolates showed inhibitory effect on the growth of Gram-positive food borne pathogens including Staphylococcus aureus, Bacillus cereus, Clostridium perfringens and Listeria monocytogenes by the agar spot test. Selected isolates were PCR-positive for nisin-encoding gene. The strains produced antibacterial substances resistant to α-amylase but sensitive to trypsin and proteinase K. Thermo-stability was indicated after treatment at 100 °C for 30 minutes. The antibacterial activity was pH dependent and occurred in pH 3 and 6, but at pH 9 the antibacterial activity was mainly restricted. No loss in antibacterial activity was recorded after treatment with SDS, Tween20, Tween 80, Triton X-100, urea and EDTA. The results suggest the potential application of these isolates as biopreservatives in food products.

Bacillus amyloliquefaciens NCPSJ7 could secrete extracellular antimicrobial substances, showing potent antifungal activities. An active peptide AFP3 was isolated from the fermentation supernatant. After chromatography, the purified peptide was tested for the fungicidal activity, molecular mass, and stability. The results indicated that the peptide with a molecular mass of around 3.3 kDa, showed discernible inhibition of the pathogen Fusarium oxysporum f. sp. niveum with the minimum fungicidal concentration of 31 µg/ml. It also exhibited excellent inhibition of some representative pathogenic fungi at a low concentration. Moreover, the peptide remained active at a wide range of temperatures and pH. Ion Na+ may even increase the antifungal activities. At the same time, the peptide could well tolerate the treatment with trypsin. Electron microscopy was used to investigate the effect of the peptide on the pathogens. The peptide inhibited the growth of pathogens by disrupting the integrity of the hyphal membranes, resulting in their lysis. The potent fungicidal activities and stability made the peptide be a candidate for a biopreservative.

The bacteriocin based strategy of biopreservation has got wide spread research interests in the recent past for their prospects in reducing usage of chemical preservatives. The bacteriocin GP1 with antibacterial activity and produced by Lactobacillus rhamnosus (L. rhamnosus) GP1 was tested for its effect on sensory (color, odor, and appearance), chemical (pH, Total Volatile Base-Nitrogen (TVB-N), Total Methyl Amine (TMA), Total Free Fatty Acid) and bacteriological (total bacterial count, count of Staphylococcus sp., Aeromonas sp., total coliform, Lactobacillus sp., Pseudomonas sp., and Vibrio sp.) quality attributes of fish filets stored at 4 and 0°C. The sensory attributes of the fish filets treated with the bacteriocin and control from 7 to 28 days of storage in both the storage temperatures varied significantly. The pH of the raw fish increased from the initial 6.8 to 7.91 and 7.43 for the control and bacteriocin GP1, respectively, at the end of storage period (28 days) when stored at 4°C. However, the pH showed a decreasing trend with the increase in period of storage for the samples stored at 0°C. The TVB-N content of the bacteriocin treated samples stored at 4°C remained within the limit of acceptability (35 mg/100 g) at the 21st day. The TMA level also remained within the acceptable limit of 10–15 mg/100 g at the 21st day in the case of bacteriocin-treated samples. The application of bacteriocin GP1 in the stored fish was effective in controlling the growth of coliforms, Aeromonas sp., Lactobacillus sp., and Vibrio sp. in the treated fish samples. The study concluded the prospects of bacteriocin GP1 as a biopreservative in storage of fish and fish products.