Search

Vijaya Juturu,1 James P Bowman,2 Jayant Deshpande1 1Department of Scientific and Clinical Affairs, OmniActive Health Technologies Inc., Morristown, NJ, 2James P Bowman & Associates LLC, Loveland, OH, USA Purpose: Carotenoids, especially lutein and zeaxanthin isomers (L/Zi), filter blue light and protect skin from environmental factors including high-energy sources. These carotenoids may be able to block the formation of melanin pathways, decrease cytokines, and increase antioxidants.Subjects and methods: This is a randomized, double-blind, placebo-controlled clinical trial over a 12-week supplementation period. Fifty healthy people (50 healthy subjects were recruited and 46 subjects completed the study) (males and females, age: 18–45 years) with mild-to-moderate dry skin were included in this study. Skin type of the subjects was classified as Fitzpatrick skin type II–IV scale. Subjects were administered with either an oral dietary supplement containing 10 mg lutein (L) and 2 mg zeaxanthin isomers (Zi) (L/Zi: RR-zeaxanthin and RS (meso)-zeaxanthin) or a placebo daily for 12 weeks. The minimal erythemal dose and skin lightening (L*) were measured via the Chromameter®. The individual typological angle was calculated. Subjective assessments were also recorded.Results: Overall skin tone was significantly improved in the L/Zi group compared to placebo (P

Nutrients introduced to the environment by finfish aquaculture pose environmental risks, which can be mitigated by robust environmental monitoring. Biological communities in soft sediments are good indicators of aquaculture derived environmental changes. Traditionally, monitoring programs have visually surveyed macrofauna communities. However, DNA metabarcoding is a potentially more efficient alternative. We compared alpha diversity, multivariate dispersion and taxonomic composition of macrofauna communities with metabarcoding derived bacterial and eukaryote communities along an organic enrichment gradient at a salmon farm in Tasmania, Australia. Additionally, we conducted a cost-benefit analysis comparing the approaches. All methods identified indicator taxa that changed in abundance over the enrichment gradient. Macrofauna analysis was the most sensitive method for detecting changes in alpha diversity, while metabarcoding was most sensitive for multivariate dispersion. Taxonomic composition of animal communities derived from the two methods differed drastically. Metabarcoding was cheaper than macrofauna for ≥93 samples and quicker for ≥14 samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 University of Tasmania. Published by Elsevier Ltd.. All rights reserved.)

When stored at chill temperatures, vacuum-packed (VP) lamb has a much shorter shelf-life than VP beef, primarily due to its higher pH, which could be linked to the higher fat content. The higher pH would create more favourable conditions for the growth of spoilage bacteria, resulting in a shorter shelf-life of meat. To determine the effects of fat on meat shelf-life as it relates to pH, a series of shelf-life trials at 2 °C were conducted using VP beef and lamb mince with varying fat contents (i.e., control with ~5%, 20%, and 50%) as a model system to red meat primal cuts. The results showed that higher fat content reduced the shelf-life of VP beef mince by 24% and lamb mince by 12.5%. This reduction was accompanied by significantly ( p < 0.05) decreased glucose and lactic acid levels. Throughout storage, a higher fat content in beef and lamb mince generally resulted in a higher pH by 0.1 ( p < 0.05) compared to the respective controls. Higher fat content mince also had faster lactic acid bacteria growth rates (by up to 0.13 Log10 CFU/g/day) and higher maximum populations of presumptive enteric bacteria up to 1.3 Log 10 CFU/g ( p < 0.05). These results suggest that fat content can negatively influence the shelf-life of VP red meat through lowering glucose and lactic acid levels, raising the pH, and increasing LAB growth rate and maximum population levels of presumptive enteric bacteria.

The stomach's acidic pH is a crucial barrier against foodborne pathogens such as Salmonella enterica. This study investigated the survival of S. enterica under simulated oral and gastric conditions (SGC; pH 2 for 120 min) as a function of intrinsic pathogen characteristics and food matrix. Fifty-seven S. enterica strains isolated from food and human infections (previously characterized by serotype, virulotype, multi-drug resistance, isolation source, and isolation season) were subjected to SGC using water as a vehicle. Population reduction among the 57 isolates ranged from 2.7 to 4.7 log CFU, revealing that human isolates were inactivated less than food isolates (p = 0.0008). Among food strains, strains isolated during the cold season (food sampled from December to February) displayed the highest reduction (p = 0.00002). Six representatives of the 57 S. enterica strains were selected according to their virulotype and antimicrobial profile. They were further used to evaluate their survival under SGC in four food matrices (water, mango, tomato, and chicken), measuring S. enterica at 30 min intervals. The strains in chicken showed the lowest reduction and inactivation rate (1.42 ± 0.35 log CFU; 0.03 ± 0.005 min -1 ), followed by tomato (3.75 ± 0.57 log CFU; 0.15 ± 0.02 min -1 ), water (4.23 ± 0.27 log CFU; 0.17 ± 0.02 min -1 ), and mango (4.49 ± 0.39 log CFU; 0.17 ± 0.03 min -1 ). These data suggest that not all S. enterica strains have the same ability to survive under SGC, influencing the probability of arriving into the small intestine., Competing Interests: Declaration of competing interest The authors declare that there is not a conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The Lactobacillaceae are lactic acid bacteria harnessed to deliver important outcomes across numerous industries, and their unambiguous, species-level identification from mixed community environments is an important endeavor. Amplicon-based metataxonomics using short-read sequencing of partial 16S rRNA gene regions is widely used to support this, however, the high genetic similarity among Lactobacillaceae species restricts our ability to confidently describe these communities even at genus level. Long-read sequencing (LRS) of the whole 16S rRNA gene or the near complete rRNA operon (16S-ITS-23S) has the potential to improve this. We explored species ambiguity amongst Lactobacillaceae using in-silico tool RibDif2, which identified allele overlap when various partial and complete 16S rRNA gene and 16S-ITS-23S rRNA regions were amplified. We subsequently implemented LRS by MinION™ to compare the capacity of V3-V4, 16S and 16S-ITS-23S rRNA amplicons to accurately describe the diversity of a 20-species Lactobacillaceae mock community in practice. In-silico analysis identified more instances of allele/species overlap with V3-V4 amplicons ( n  = 43) compared to the 16S rRNA gene ( n  = 11) and partial ( n  = up to 15) or complete ( n  = 0) 16S-ITS-23S rRNA amplicons. With subsequent LRS of a DNA mock community, 80% of target species were identified using V3-V4 amplicons whilst the 16S rRNA gene and 16S-ITS-23S rRNA region amplicons resulted in 95 and 100% of target species being identified. A considerable reduction in false-positive identifications was also seen with 16S rRNA gene ( n  = 3) and 16S-ITS-23S rRNA region ( n  = 9) amplicons compared with V3-V4 amplicons ( n  = 43). Whilst the target species affected by allele overlap in V3-V4 and 16S rRNA gene sequenced mock communities were predicted by RibDif2, unpredicted species ambiguity was observed in 16S-ITS-23S rRNA sequenced communities. Considering the average nucleotide identity (ANI) between ambiguous species (~97%) and the basecall accuracy of our MinION™ sequencing protocol (96.4%), the misassignment of reads between closely related taxa is to be expected. With basecall accuracy exceeding 99% for recent MinION™ releases, the increased species-level differentiating power promised by longer amplicons like the 16S-ITS-23S rRNA region, may soon be fully realized., Competing Interests: SO, MB, and BC were employed by Quantal Bioscience Pty Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Olivier, Bull, Strube, Murphy, Ross, Bowman and Chapman.)

Leafy green vegetables (LGVs) have large surface areas and can be colonized by various microorganisms including pathogens. In this study, we investigated the effect of pre-harvest sanitizer treatments on the survival of inoculated proxy pathogen Listeria innocua ATCC 33090 and the natural microbial community of mizuna, rocket (arugula), red chard and spinach grown under commercial conditions. Electrolyzed water (e-water), peracetic acid (PAA), and 1-bromo-3-chloro-5-dimethylhydantoin (BCDMH) were tested against water controls. We also observed the subsequent sensorial changes of harvested, bagged LGV leaves over a period of 12 days within chill storage alongside the growth, diversity and structure of bacterial populations determined using 16S rRNA gene amplicon sequencing and total viable counts (TVC). Treatment with PAA resulted in the highest reductions of L. innocua (2.4-5.5 log units) compared to the other treatments (0.25-2.5 log units). On day 0 (24 h after sanitizer application), the TVC on sanitizer treated LGVs were significantly reduced compared to water controls, except for rocket. During storage at 4.5 (±0.5)°C sanitisers only hindered microbial growth on LGVs initially and did not influence final bacterial population levels, growth rates or changes in LGV sample colour, decay, odour and texture compared to water controls. Shelf-life was not extended nor was it reduced. The community structure on LGV types differed though a core set of bacterial amplicon sequence variants (ASV) were present across all samples. No significant differences were observed in bacterial diversity between sanitizer treatments, however sanitizer treated LGV samples had initially reduced diversity compared to water treated samples. The bacterial compositions observed at the end point of storage considerably differed from what was observed at initial point owing to the increase in abundance of specific bacterial taxa, mainly Pseudomonas spp., the abundance and growth responses differing between LGV types studied. This study provides a better understanding on the microbiology and sensory impact of pre-harvest applied sanitiser treatments on different LGVs destined for commercial food use., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Resin canal discoloration (RCD) severely impacts the fruit quality of mango, diminishes consumer confidence, and reduces sales, but the biological cause is still unclear. Using next-generation sequencing, the overall microbial community composition of RCD+ and visually healthy mango fruits was determined for the first time to examine the possible role of bacterial and fungal pathogens in RCD. The diversity profile of bacterial and fungal communities was determined using primers targeting the 16S rRNA gene and Internal Transcribed Spacer (ITS) regions. Results showed that bacterial communities in healthy fruits are clustered together and significantly different from those in RCD+ fruits. Tatumella and Pantoea species were the most abundant bacterial taxa on RCD+ fruit, and both have been linked to disease outbreaks in a variety of fruit crops. Fungal communities were generally similar between RCD+ and normal samples, though non-pathogenic yeasts Meyerozyma and Naganishia tended to dominate the fungal communities on RCD+ fruit. The study indicates that bacteria rather than fungal organisms are more likely to be associated with RCD in mango. This finding will facilitate the isolation and confirmation of RCD-causing organisms and the development of control strategies to manage RCD problem in mango., (© The Author(s) 2023. Published by Oxford University Press on behalf of Applied Microbiology International.)

Fish aquaculture is a rapidly expanding global industry, set to support growing demands for sources of marine protein. Enhancing feed efficiency (FE) in farmed fish is required to reduce production costs and improve sector sustainability. Recognising that organisms are complex systems whose emerging phenotypes are the product of multiple interacting molecular processes, systems-based approaches are expected to deliver new biological insights into FE and growth performance. Here, we establish 14 diverse layers of multi-omics and clinical covariates to assess their capacities to predict FE and associated performance traits in a fish model ( Oncorhynchus tshawytscha ) and uncover the influential variables. Inter-omic relatedness between the different layers revealed several significant concordances, particularly between datasets originating from similar material/tissue and between blood indicators and some of the proteomic (liver), metabolomic (liver), and microbiomic layers. Single- and multi-layer random forest (RF) regression models showed that integration of all data layers provide greater FE prediction power than any single-layer model alone. Although FE was among the most challenging of the traits we attempted to predict, the mean accuracy of 40 different FE models in terms of root-mean square errors normalized to percentage was 30.4%, supporting RF as a feature selection tool and approach for complex trait prediction. Major contributions to the integrated FE models were derived from layers of proteomic and metabolomic data, with substantial influence also provided by the lipid composition layer. A correlation matrix of the top 27 variables in the models highlighted FE trait-associations with faecal bacteria ( Serratia spp.), palmitic and nervonic acid moieties in whole body lipids, levels of free glycerol in muscle, and N-acetylglutamic acid content in liver. In summary, we identified subsets of molecular characteristics for the assessment of commercially relevant performance-based metrics in farmed Chinook salmon.

Based on genome-wide data, Massilia species belonging to the clade including Telluria mixta LMG 11547 T should be entirely transferred to the genus Telluria owing to the nomenclatural priority of the type species Telluria mixta . This results in the transfer of 35 Massilia species to the genus Telluria . The presented data also supports the creation of two new genera since peripherally branching Massilia species are distinct from Telluria and other related genera. It is proposed that 13 Massilia species are transferred to Mokoshia gen. nov. with the type species designated Mokoshia eurypsychrophila comb. nov. The species Massilia arenosa is proposed to belong to the genus Zemynaea gen. nov. as the type species Zemynaea arenosa comb. nov. The genome-wide analysis was well supported by canonical ordination analysis of Enzyme Commission (EC) codes annotated from genomes via pannzer2. This new approach was performed to assess the conclusions of the genome-based data and reduce possible ambiguity in the taxonomic decision making. Cross-validation of EC code data compared within canonical plots validated the reclassifications and correctly visualized the expected genus-level taxonomic relationships. The approach is complementary to genome-wide methodology and could be used for testing sequence alignment based data across genetically related genera. In addition to the proposed broader reclassifications, invalidly described species ' Massilia antibiotica ', ' Massilia aromaticivorans ', ' Massilia cellulosiltytica ' and ' Massilia humi ' are described as Telluria antibiotica sp. nov., Telluria aromaticivorans sp. nov., Telluria cellulosilytica sp. nov. and Pseudoduganella humi sp. nov., respectively. In addition, Telluria chitinolytica is reclassified as Pseudoduganella chitinolytica comb. nov. The use of combined genome-wide and annotation descriptors compared using canonical ordination clarifies the taxonomy of Telluria and its sibling genera and provides another way to evaluate complex taxonomic data.

In this study a data dependent acquisition label-free based proteomics approach was used to identify pH-dependent proteins that respond in a growth phase independent manner in Campylobacter jejuni reference strain NCTC 11168. NCTC 11168 was grown within its pH physiological normal growth range (pH 5.8, 7.0 and 8.0, μ = ∼0.5 h -1 ) and exposed to pH 4.0 shock for 2 h. It was discovered that gluconate 2-dehydrogenase GdhAB, NssR-regulated globins Cgb and Ctb, cupin domain protein Cj0761, cytochrome c protein CccC (Cj0037c), and phosphate-binding transporter protein PstB all show acidic pH dependent abundance increases but are not activated by sub-lethal acid shock. Glutamate synthase (GLtBD) and the MfrABC and NapAGL respiratory complexes were induced in cells grown at pH 8.0. The response to pH stress by C. jejuni is to bolster microaerobic respiration and at pH 8.0 this is assisted by accumulation of glutamate the conversion of which could bolster fumarate respiration. The pH dependent proteins linked to growth in C. jejuni NCTC 11168 aids cellular energy conservation maximising growth rate and thus competitiveness and fitness., Competing Interests: Declaration of competing interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Bacillus cereus phylogenetic group III and IV strains are commonly associated with food products and cause toxin mediated foodborne diseases. These pathogenic strains have been identified from milk and dairy products, such as reconstituted infant formula and several cheeses. Paneer is a fresh, soft cheese originating from India that is prone to foodborne pathogen contamination, such as by Bacillus cereus. However, there are no reported studies of B. cereus toxin formation in paneer or predictive models quantifying growth of the pathogen in paneer under different environmental conditions. This study assessed enterotoxin-producing potential of B. cereus group III and IV strains, isolated from dairy farm environments, in fresh paneer. Growth of a four-strain cocktail of toxin-producing B. cereus strains was measured in freshly prepared paneer incubated at 5-55 °C and modelled using a one-step parameter estimation combined with bootstrap re-sampling to generate confidence intervals for model parameters. The pathogen grew in paneer between 10 and 50 °C and the developed model fit the observed data well (R 2  = 0.972, RMSE = 0.321 log 10  CFU/g). The cardinal parameters for B. cereus growth in paneer along with the 95% confidence intervals were: μ opt 0.812 log 10  CFU/g/h (0.742, 0.917); T opt is 44.177 °C (43.16, 45.49); T min is 4.405 °C (3.973, 4.829); T max is 50.676 °C (50.367, 51.144). The model developed can be used in food safety management plans and risk assessments to improve safety of paneer while also adding to limited information on B. cereus growth kinetics in dairy products., Competing Interests: Declarations of competing interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Lamb meat is an important export commodity, however chilled vacuum-packed (VP) lamb has approximately half the shelf-life of beef under the same storage conditions. This makes the industry more vulnerable to financial losses due to long shipping times and unexpected spoilage. Understanding the spoilage mechanisms of chilled VP lamb in relation to VP beef is important for developing effective strategies to extend the shelf-life of lamb. This review has discussed various key factors (i.e., pH, fat, and presence of bone) that have effects on microbial spoilage of VP lamb contributing to its shorter shelf-life relative to VP beef. A range of bacterial organisms and their metabolisms in relevance to lamb spoilage are also discussed. The data gap in the literature regarding the potential mechanisms of spoilage in VP red meat is highlighted. This review has provided the current understanding of key factors affecting the shelf-life of VP lamb relative to VP beef. It has also identified key areas of research to further understand the spoilage mechanisms of VP lamb. These include investigating the potential influence of fat and bone (including bone marrow) on the shelf-life, as well as assessing changes in the meat metabolome as the spoilage microbial community is developing using an integrated approach. Such new knowledge would aid the development of effective approaches to extend the shelf-life of VP lamb., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Gut microbiota play important roles in fish health and growth performance and the microbiome in fish has been shown to be a biomarker for stress. In this study, we surveyed the change of Chinook salmon ( Oncorhynchus tshawytscha ) gut and water microbiota in freshwater recirculating aquaculture systems (RAS) for 7 months and evaluated how gut microbial communities were influenced by fish health and growth performance. The gut microbial diversity significantly increased in parallel with the growth of the fish. The dominant gut microbiota shifted from a predominance of Firmicutes to Proteobacteria, while Proteobacteria constantly dominated the water microbiota. Photobacterium sp. was persistently the major gut microbial community member during the whole experiment and was identified as the core gut microbiota for freshwater farmed Chinook salmon. No significant variation in gut microbial diversity and composition was observed among fish with different growth performance. At the end of the trial, 36 out of 78 fish had fluid in their swim bladders. These fish had gut microbiomes containing elevated proportions of Enterococcus, Stenotrophomonas , Aeromonas, and Raoultella . Our study supports the growing body of knowledge about the beneficial microbiota associated with modern salmon aquaculture systems and provides additional information on possible links between dysbiosis and gut microbiota for Chinook salmon., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zhao, Symonds, Walker, Steiner, Carter, Bowman and Nowak.)

To prevent and control foodborne diseases, there is a fundamental need to identify the foods that are most likely to cause illness. The goal of this study was to rank 25 commonly consumed food products associated with Salmonella enterica contamination in the Central Region of Mexico. A multicriteria decision analysis (MCDA) framework was developed to obtain an S. enterica risk score for each food product based on four criteria: probability of exposure to S. enterica through domestic food consumption (Se); S. enterica growth potential during home storage (Sg); per capita consumption (Pcc); and food attribution of S. enterica outbreak (So). Risk scores were calculated by the equation Se*W 1 +Sg*W 2 +Pcc*W 3 +So*W 4 , where each criterion was assigned a normalized value (1-5) and the relative weights (W) were defined by 22 experts' opinion. Se had the largest effect on the risk score being the criterion with the highest weight (35%; IC95% 20%-60%), followed by So (24%; 5%-50%), Sg (23%; 10%-40%), and Pcc (18%; 10%-35%). The results identified chicken (4.4 ± 0.6), pork (4.2 ± 0.6), and beef (4.2 ± 0.5) as the highest risk foods, followed by seed fruits (3.6 ± 0.5), tropical fruits (3.4 ± 0.4), and dried fruits and nuts (3.4 ± 0.5), while the food products with the lowest risk were yogurt (2.1 ± 0.3), chorizo (2.1 ± 0.4), and cream (2.0 ± 0.3). Approaches with expert-based weighting and equal weighting showed good correlation (R 2  = 0.96) and did not show significant differences among the ranking order in the top 20 tier. This study can help risk managers select interventions and develop targeted surveillance programs against S. enterica in high-risk food products., (© 2022 Society for Risk Analysis.)

Peracetic acid (PAA) applied to whole poultry carcasses can reduce the number of Campylobacter, a leading cause of human gastroenteritis. However, previous modelling experiments indicated that Campylobacter survived in greater numbers when pre-treated with a thermal stress equivalent to poultry processing scalding prior to chilling with PAA than when subject to chilling with PAA only. To better understand how Campylobacter responds to PAA, proteomes of C. jejuni poultry strain 2704 were measured after exposure to PAA (60 ppm, pH 4.0) for 45 min under laboratory ambient conditions (approximately 23 °C) to establish a foundational map of survival mechanism before combining with other stresses. Analysis of 580 quantified proteins did not indicate a triggered "peroxide shock" response, nor were common heat shock responses detected. Thioredoxin, iron homeostatic, peroxiredoxins and cytochrome c peroxidases became more abundant suggesting that PAA disturbed cytoplasmic redox homeostasis resulting in antioxidant activation and increased prioritisation of iron homeostasis. The PAA treatment led to responses that included an increased priority for oxidative phosphorylation and a simultaneous decrease in central metabolism associated protein abundances. Lon protease was induced suggesting it has a role in maintaining homeostasis during non-thermal stress. Proteins in flagella and chemotaxis became more abundant though whether PAA has a chemorepellent effect requires further investigation. Overall, the proteome data suggests there was a rapid cellular response to applied PAA stress in the first 15 min with the adaptation to the stress completing between 30 and 45 min. The findings will help guide PAA implementation in commercial poultry processing in terms of processing location and length of application., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Chicken meat is often associated withSalmonella entericacontamination worldwide. This study proposes a risk assessment model for human salmonellosis linked to the domestic consumption of chicken meat in the central region of Mexico, incorporating genotypic and phenotypic data. SixS. entericagroups were used, considering the presence of specific virulence genes and multidrug resistance (MDR). Sixteen exposure scenarios were established considering retail point (RP1 = fresh market/butcher shop; RP2 = mini-super/supermarket), transportation, home storage, cooking, and cross-contamination. The model predicted a mean annual salmonellosis cases of 66,754 due to chicken consumption (CI95% 10775-231606). The mean probability of illness (P ill ) among the exposure scenarios ranged from 2.5 × 10 -9 to 3.7 × 10 -6 , 7.7 × 10 -8 to 1.1 × 10 -4 , and 6.7 × 10 -4 to 7.8 × 10 -2 for low, moderate, and high virulence groups. Exposure scenarios with the highest P ill were not responsible for most cases due to their low frequency of occurrence. The high virulence/ MDR group was responsible for most cases (66.5 %), despite the low S. enterica prevalence (RP1 0.5 % and RP2 5.0 %). The years lost due to disability (YLD) value for MDR was 2.6 × higher than for non-MDR. Spearman rank showed that the inputs with higher influence on the variability of salmonellosis depended on the type of exposure scenario. For example, the cooking temperature and time had the most significant influence in the scenarios where S. enterica can survive after cooking. Including the microbial genotypic and phenotypic characteristics in risk assessment modeling highlights the importance of focusing on high-virulent and MDR strains, which are not the most frequent but represent the highest public health risk., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The objective of this study was to establish whether specific organisms play important roles in the spoilage rate of vacuum-packed (VP) lamb at low storage temperatures. The spoilage potential of representative organisms (n = 13) of the spoilage community of VP lamb were investigated through a series of shelf-life challenge trials. Each isolate was individually inoculated onto sterile (irradiated) and non-sterile (i.e., containing natural microbial community) VP lamb meat. Meat quality was assessed over time by measuring sensorial qualities, bacterial growth and pH. Among all test organisms, Clostridium spp. had the highest spoilage potential and had a major effect on the spoilage rate of VP lamb (based on sensory assessment). C. estertheticum caused premature 'blown pack' spoilage; however, the spoilage was delayed in a community setting. C. putrefaciens and C. algidicarnis caused premature spoilage of VP lamb independently and in a community setting. In contrast, all facultative anaerobes and Pseudomonas sp. tested were not capable of spoiling meat independently or within a community, expect for Carnobacterium divergens and Serratia spp., which spoiled meat prematurely when present in a community. Overall, these results highlight that Clostridium could be one of the main taxa driving the faster rate of quality loss of chilled VP lamb compared to beef. This research can help to inform opportunities for shelf-life extension by targeting organisms with 'high' spoilage potential, such as Clostridium., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Finfish aquaculture is a fast-growing primary industry and is increasingly common in coastal ecosystems. Bacterioplankton is ubiquitous in marine environment and respond rapidly to environmental changes. Changes in bacterioplankton community are not well understood in semi-enclosed stratified embayments. This study aims to examine aquaculture effects in the composition and functional profiles of the bacterioplankton community using amplicon sequencing along a distance gradient from two finfish leases in a marine embayment. Results revealed natural stratification in bacterioplankton associated to NOx, conductivity, salinity, temperature and PO 4 . Among the differentially abundant bacteria in leases, we found members associated with nutrient enrichment and aquaculture activities. Abundant predicted functions near leases were assigned to organic matter degradation, fermentation, and antibiotic resistance. This study provides a first effort to describe changes in the bacterioplankton community composition and function due to finfish aquaculture in a semi-enclosed and highly stratified embayment with a significant freshwater input., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Vacuum-packed lamb produced in Australia has a shelf-life of 80-90 days under export conditions (-1 to 0 °C). However, access to some markets could involve >90 days transit time. Studies to understand the potential mechanisms of microbial spoilage of vacuum-packed lamb are, therefore, important to assist the development of shelf-life extension methods. Here, we investigated the effects of glucose on the shelf-life of vacuum-packed lamb. This was done by adding glucose (up to 4.64 mmol/kg) to the surface of meat and conducting a series of shelf-life trials, in which the sensorial qualities, bacterial growth, pH, and residual glucose and lactic acid were measured over time. Based on sensory analysis glucose extended the shelf-life, ranging from 8% to >76% increase relative to the control. Glucose reduced meat pH, potentially affecting the microbial community composition and the accumulation of spoilage metabolites. These results indicate that glucose plays an important role in microbial spoilage of vacuum-packed lamb possibly by pH reduction., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

To estimate human exposure to Salmonella enterica, it is essential to understand the pathogen distribution and characteristics. Prevalence and concentration of S. enterica were determined in mango, tomato, and raw chicken samples purchased in three states (Aguascalientes, Querétaro, and Guadalajara) located in the central region of Mexico during two seasons. In addition, S. enterica isolates were characterized by absence/presence of 13 virulence genes (chromosomal, prophage, and plasmid) and resistance to 14 antibiotics. A total of 300 samples of mango, 272 of tomato, and 354 of raw chicken were analyzed. The mean of the prevalence (24.9%) and concentration (-0.61 Log MPN/g) of S. enterica in chicken was higher than in mango (1.3%, -1.7 Log MPN/g) and tomato (1.1%, -1.7 Log MPN). Among S. enterica isolates (284), there were 7 different virulotypes, belonging 68.7% of isolates to V2; there was high variability in the presence of mobile genetic elements. The occurrence of specific mobile elements ranged from 81.4% to 11.3% among isolates. Among the isolates, 91.5% were resistant to at least one antibiotic with ampicillin being the most frequent; 54.9% of isolates were multidrug resistant. Data from this study can be used for quantitative microbial risk assessment of S. enterica related to mango, tomato, and raw chicken consumption in the central region of Mexico. PRACTICAL APPLICATION: Data on the prevalence and concentration of Salmonella enterica obtained in this study can be used to estimate the exposure assessment for the consumption of mango, tomato, and chicken in the central region of Mexico. In addition, the characteristics of the S. enterica isolates could be used to select representative strains for future studies to evaluate the intraspecies variability., (© 2021 Institute of Food Technologists®.)

The distinctive flavours in hard cheeses are attributed largely to the activity of nonstarter lactic acid bacteria (NSLAB) which dominate the cheese matrix during maturation after lactose is consumed. Understanding how different strains of NSLAB survive, compete, and scavenge available nutrients is fundamental to selecting strains as potential adjunct starters which may influence product traits. Three Lacticaseibacillus paracasei isolates which dominated at different stages over 63-week maturation periods of Australian Cheddar cheeses had the same molecular biotype. They shared many phenotypic traits, including salt tolerance, optimum growth temperature, growth on N-acetylglucosamine and N-acetylgalactosamine plus delayed growth on D-ribose, carbon sources likely present in cheese due to bacterial autolysis. However, strains 124 and 163 (later named GCRL163) survived longer at low pH and grew on D-tagatose and D-mannitol, differentiating this phenotype from strain 122. When cultured on growth-limiting lactose (0.2%, wt/vol) in the presence of high concentrations of L-leucine and other amino acids, GCRL163 produced, and subsequently consumed lactate, forming acetic and formic acids, and demonstrated temporal accumulation of intermediates in pyruvate metabolism in long-term cultures. Strain GCRL163 grew in Tween 80-tryptone broths, a trait not shared by all L. casei-group dairy isolates screened in this study. Including citrate in this medium stimulated growth of GCRL163 above citrate alone, suggesting cometabolism of citrate and Tween 80. Proteomic analysis of cytosolic proteins indicated that growth in Tween 80 produced a higher stress state and increased relative abundance of three cell envelope proteinases (CEPs) (including PrtP and Dumpy), amongst over 230 differentially expressed proteins., (© The Author(s) 2021. Published by Oxford University Press on behalf of Society of Industrial Microbiology and Biotechnology.)

Paneer is a fresh, soft ready-to-eat cheese that is susceptible to Listeria monocytogenes contamination, exemplified by product recalls in Australia, Canada, and the USA. Previous research demonstrates that L. monocytogenes grows in paneer, however there are no paneer-specific predictive models that quantify the effect of environmental conditions on L. monocytogenes viability. This study measured the viability of a five-strain cocktail of L. monocytogenes in freshly prepared paneer incubated at 4-40 °C. Growth rates were fitted with the extended Ratkowsky square root model, with growth rates ranging from 0.014 to 0.352 log 10  CFU/h. In comparison with published models, only the ComBase L. monocytogenes broth model acceptably predicted growth (B f = 1.01, A f = 1.12) versus the developed model. The influence of paneer pH (5.0-6.0) and storage temperature (41-45 °C) on L. monocytogenes growth at the upper temperature growth boundary was described using a logistic model. These models provide quantitative tools to improve the safety of paneer processing conditions, shelf-life estimation, food safety management plans, and risk assessment., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The ability of Listeria monocytogenes isolates to survive within the food production environment (FPE), as well as virulence, varies greatly between strains. There are specific genetic determinants that have been identified which can strongly influence a strains ability to survive in the FPE and/or within human hosts. In this study, we assessed the FPE fitness and virulence potential, including efficacy of selected hygiene or treatment intervention, against 52 L. monocytogenes strains isolated from various food and food environment sources. Phenotypic tests were performed to determine the minimum inhibitory concentration of cadmium chloride and benzalkonium chloride and the sensitivities to five clinically relevant antibiotics. A genomic analysis was also performed to identify resistance genes correlating to the observed phenotypic resistance profiles, along with genetic determinants of interest which may elude to the FPE fitness and virulence potential. A transposon element containing a novel cadmium resistance gene, cadA7, a Tn916 variant insert in the hypervariable Listeria genomic island 1 region and an LGI2 variant were identified. Resistance to cadmium and disinfectants was prevalent among isolates in this study, although no resistance to clinically important antimicrobials was observed. Potential hypervirulent strains containing full length inlA, LIPI-1 and LIPI-3 were also identified in this study. Cumulatively, the results of this study show a vast array of FPE survival and pathogenicity potential among food production-associated isolates, which may be of concern for food processing operators and clinicians regarding L. monocytogenes strains colonising and persisting within the FPE, and subsequently contaminating food products then causing disease in at risk population groups., (Copyright © 2021 Elsevier B.V. All rights reserved.)