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An outlook on the current status of different strategies for magnetic micro- and nanosized bead functionalization with aptamers as prominent bioreceptors is given with a focus on electrochemical and optical apta-assays, as well as on aptamer-modified magnetic bead–based miniaturized extraction techniques in food control. Critical aspects that affect interaction of aptamers with target molecules, as well as the possible side effects caused by aptamer interaction with other molecules due to non-specific binding, are discussed. Challenges concerning the real potential and limitations of aptamers as bioreceptors when facing analytical problems in food control are addressed. Graphical abstract

Seafood is the product most susceptible to fraudulent activities. In particular, the cephalopod sector is affected mainly by the replacement of fresh by frozen-thawed product either immediately or after bleaching with hydrogen peroxide. Such activities undermine the consumers' confidence in the fish industry and in the effectiveness of the government's food control programme. Currently, the conventional analyses performed to check food authenticity are time-consuming and require skilled personnel, and thus are not applicable to on-site control. The aim of the present study was to develop classification models to discriminate cuttlefish (Sepia officinalis) according to physical status and hydrogen peroxide treatment among fresh, frozen-thawed and frozen-thawed hydrogen peroxide-treated samples. A total of 669 cuttlefish spectra were collected, under real conditions, using a portable near-infrared spectrometer (902–1680 nm) operating in reflectance mode. Classification models were developed and then validated using a Support Vector Machine algorithm. Performance of the models was tested through external and hold-out validation according to their accuracy, sensitivity, specificity and Matthew correlation coefficient. The best performance was observed in discriminating between fresh and frozen-thawed product, in which were observed in hold-out validation 0.97 in accuracy and sensitivity, 0.96 in specificity, and 0.92 in Matthew correlation coefficient; whereas, an accuracy of 0.93, sensitivity of 0.89, specificity of 0.94 and Matthew correlation coefficient of 0.83 were found in external validation. However, sample classification according to bleaching treatment showed high performance when fresh samples were excluded. Such achievements confirm the applicability of near-infrared spectroscopy to the on-site inspection of cuttlefish and the control of the fraudulent activity of replacing fresh fish with product mislabelled as such.

Due to legal regulations, the rise of globalised (online) commerce and the need for public health protection, the analysis of spirit drinks (alcoholic beverages &gt, 15% vol) is a task with growing importance for governmental and commercial laboratories. In this article a newly developed method using nuclear magnetic resonance (NMR) spectroscopy for the simultaneous determination of 15 substances relevant to assessing the quality and authenticity of spirit drinks is described. The new method starts with a simple and rapid sample preparation and does not need an internal standard. For each sample, a group of 1H-NMR spectra is recorded, among them a two-dimensional spectrum for analyte identification and one-dimensional spectra with suppression of solvent signals for quantification. Using the Pulse Length Based Concentration Determination (PULCON) method, concentrations are calculated from curve fits of the characteristic signals for each analyte. The optimisation of the spectra, their evaluation and the transfer of the results are done fully automatically. Glucose, fructose, sucrose, acetic acid, citric acid, formic acid, ethyl acetate, ethyl lactate, acetaldehyde, methanol, n-propanol, isobutanol, isopentanol, 2-phenylethanol and 5-(hydroxymethyl)furfural (HMF) can be quantified with an overall accuracy better than 8%. This new NMR-based targeted quantification method enables the simultaneous and efficient quantification of relevant spirit drinks ingredients in their typical concentration ranges in one process with good accuracy. It has proven to be a reliable method for all kinds of spirit drinks in routine food control.

To safeguard the consumers’ well-being, it is necessary to develop novel methods for determination of carcinogens in food, including volatiles generated during frying. The currently used procedures for analysis of volatile fraction of vegetable oils are not based on real-time measurements and thus do not enable the determination of carcinogenic compounds in frying fumes; instead, only the headspace or liquid fraction is sampled. In this article, described is an approach in which proton transfer reaction mass spectrometry with time-of-flight analyser (PTR-TOFMS) was used for real-time monitoring of carcinogenic compounds generated during thermal degradation of rapeseed oil. Using PTR-MS, it was possible to monitor the concentration of known volatile carcinogens according to the International Agency for Research on Cancer (IARC), alongside BTEX compounds, acrolein, and selected aldehydes. Moreover, the applicability of several supervised data analysis methods for the classification of oil samples according to their degree of thermal degradation was presented, with best results obtained using the k-nearest neighbours algorithm. Proton transfer reaction mass spectrometry is a powerful technique for the determination of carcinogenic compounds generated during thermal degradation of edible oils. Further investigation of the chemical processes which occur during frying can lead to improvement of food safety. Graphical abstract

A low-cost and portable LED photometer was developed and applied for the in situ determination of urea in milk. The determination was based on Berthelot’s reaction. After optimization, the best experimental variables, the detection limit and quantification limit were 1.8 × 10^−4 and 8.0 × 10^−4 mol L^−1, respectively. The percentage recovery varied between 95.6 and 105%. The paired t test was performed for the cow and goat milk determination and the results agreed at a 95% level of confidence for the in situ determination. Supported by the results, the analytical method based on LED photometer demonstrated that it can be employed for urea determination in food production for quality purpose, and small rural producers can evaluate the quality of herd feeding due to the easy handling, portability, fast instrumental response, and low cost of the materials used.

Oil blending is often used to enhance the properties of vegetable oils. The admixture of a more thermally stable oil makes the resulting blend more suitable for use in frying. A new method of quality assessment of vegetable oils used in frying is presented in this paper. In this method, ultra-fast gas chromatography coupled with flame ionization detector and chemometrics is employed. Principal component analysis was used for data processing. The results obtained with this method were compared with the results of the Rancimat test and sensory evaluation. It is demonstrated that the addition of olive oil improves the stability of rapeseed oil, and also changes its flavour and aroma profile. In addition, it was found that ultra-fast GC coupled with chemometrics is an effective tool for the assessment of the quality of edible oils. The proposed method does not require sample preparation, and the total time of analysis is less than 2 min. Graphical abstract

A new electroanalytical method has been developed for the determination of polar antioxidant compounds in extra virgin olive oils. This method is based on the extraction of polar antioxidant compounds from extra-virgin olive oils by means of a deep eutectic solvent and their determination by a modified screen-printed electrode platform. The platform sensitivity was increased by modifying the working electrode with MWCNT and TiO2 nanoparticles as modifiers and Nafion as a binder. The platform showed very good sensitivity in detecting polar antioxidant compounds in extra-virgin olive oils in a fairly wide range of concentrations. The measurements were performed by using square wave voltammetry. The extraction was performed without using organic solvents, making the method environmentally friendly. The proposed method has been compared with a common spectrophotometric one, the results appeared in good agreement. The method is sufficiently easy and quick to be used for screening analyses of polar antioxidant compounds in extra-virgin olive oils on the field.

The biomolecular characterization of edible products is gaining an increasing importance in food chemistry. The characteristic aroma or bouquet of a wine is the result of complex interactions of volatile molecules and odor receptors. Its characterization is the subject of many different studies, aimed at the development of new methods to be used for the discovery of frauds and for the typization of Protected Designation of Origin (P.D.O.) or Protected Geographic Indication (P.G.I.) wines. We previously outlined the proteomic profile of three cultivars of Vitis vinifera from South Italy (Campania) used for white wine production (Fiano, Greco and Falanghina) during the ripening. In this work, we present a mass spectrometry based study aimed at obtaining the profile of volatiles on the same samples using solid phase micro extraction coupled to gas chromatography. We demonstrated that some of the main constituents of aroma (namely terpenes, alcohols, aldehydes, etc.) were characteristic of certain grapes and absent in others.

The application of stilbenes in the food industry is being considered because of their biological activities. Piceatannol, pterostilbene and ε-viniferin have awakened the industry’s interest. However, before they can be commercialized, we must first guarantee their safety for consumers. The present work reviews the toxicological studies performed with these stilbenes. A wide variety of studies has demonstrated their cytotoxic effects in both cancer and non-cancerous cell lines. In contrast, although DNA damage was detected by some authors, in vitro genotoxic studies on the effects of piceatannol, pterostilbene, and ε-viniferin remain scarce. None of the three reviewed substances have been evaluated using the in vitro tests required by the European Food Safety Authority (EFSA) as the first step in genotoxicity testing. We did not find any study on the toxic effects of these stilbenes in vivo. Thus, more studies are needed to confirm their safe use before they can be authorized as additive in the food industry. España Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación and INIA project (RTA2015-00005-C02-02

Scientific research in the nanomaterials field is constantly evolving, making it possible to develop new materials and above all to find new applications. Therefore, nanoparticles (NPs) are suitable for different applications: nanomedicine, drug delivery, sensors, optoelectronics and food control. This review explores the recent trend in food control of using noble metallic nanoparticles as determination tools. Two major uses of NPs in food control have been found: the determination of contaminants and bioactive compounds. Applications were found for the determination of mycotoxins, pesticides, drug residues, allergens, probable carcinogenic compounds, bacteria, amino acids, gluten and antioxidants. The new developed methods are competitive for their use in food control, demonstrated by their validation and application to real samples.

A low-cost and portable LED-based photometer was developed and applied for in situ determination of copper in sugarcane spirit. The determination was based on the chelation reaction between copper(II) and cuprizone (bis(cyclohexanone)oxalyldihydrazone). After optimizing the best experimental variables, a dynamic linear range to determine copper(II) was linear from 1.0 to 12.0 mg L−1 (r2 = 0.999) with the limits of detection and quantification of 0.20 and 0.70 mg L−1, respectively. The recovery of copper ranged from 96.5 to 104.4%. The paired t test was performed, and the results agreed at 95% level of confidence. The analytical method LED-based photometer demonstrated that it can be employed to determine copper in sugarcane spirit for quality purpose, e.g., small rural producers can evaluate the drink quality before bottling due to the easy handling, portability, fast response, and low-cost of the materials used.

Artemisia campestris L. (Asteraceae) is a polymorphic species that consists of many subspecies and varieties. It is known for its medicinal, pharmacological, and culinary properties. This review is undertaken with the aim to highlight some aspects of this plant, specifically the taxonomy, the cytogeography, the phytochemistry with an emphasis on the structure-activity relationship (SAR) of the main bioactive compounds of A. campestris L. in addition to its biological properties and the food control properties. The bibliographic data compiled in this review allowed the revision of 146 papers, by using different databases and scientific engines, such as Scopus, ScienceDirect, Pubmed, and google scholar. The taxonomic analysis has embedded A. campestris L. in the tribe Anthemideae, and the genus Artemisia L. Also many subtaxa have been identified, and a subspecific classification of this species has been established on the basis of its botanical characters. The cytogenetic findings evidenced that A.campestris L. is prevailed by the chromosome number x = 9, with a polyploidization degree ranging from diploidy to hexaploidy according to the geographical distribution of the plant populations, while the genome size seems to be proportional to the ploidy level, suggesting an adaptive trait of the cytotypes to new environments. This plant is rich in polyphenols, flavonoids, and terpenic compounds, which substantiate the bioactivities attributed to its extracts and essential oil. Hence, the SAR of the main bioactive compounds of A. campestris L., mainly the prominent flavonoids, phenolic acids, and terpenes revealed a tight link between specific chemical entities of the bioactive compound and the respective biological activity. Many biological activities were approached in this review, mainly the antioxidant, antivenom, antidiabetic, antihyperlipidemic, anti-inflammatory, antihypertensive, anti-leishmaniasis, antinociceptive, wound healing, and analgesic activities in addition to the hepatoprotective, nephroprotective, neuroprotective, and gastroprotective actions. Finally, the food preservative ability of the extracts and essential oil obtained from A.campestris L. have been fully discussed. The present review contributes to the literature, by bringing more clarifications about the different aspects of A.campestris L., like taxonomy, cytogeography and biological interests of this species. The SAR approach of some constituents that occur in A.campestris L., gives a solid support that can be used to explore the bioactivity of components isolated from this species, while the preservative properties of this plant can be usefully exploited for the agrifood sector.

Carvacrol is a volatile monoterpenic phenol and main component of oregano essential oil that shows nonspecific antimicrobial activity against foodborne pathogenic bacteria. Fish-skin gelatin (FSG) nanofibers encapsulating carvacrol (15%, 20%, 25%, and 30%, w/w FSG) were successfully prepared via solution blow-spinning (SBS) technique using lecithin (2.475% wb) as the surfactant. FSG emulsions with lower carvacrol ratios (5% and 10%) showed higher values in particle size and surface tension as well as lower values in viscosity and modulus, which led to failure of maintaining nanofibers shape. The formed carvacrol-FSG nanofibers showed round and smooth morphologies with average fiber diameters ranging from 103.2 to 138.1 nm as the carvacrol ratio increased from 15% to 30%. Carvacrol was evenly dispersed within the interior of nanofiber matrix. All carvacrol-FSG nanofibers showed inhibitive effects against the growth of Escherichia coli, Salmonella enterica, and Listeria monocytogenes. Moreover, nanofibers with lower carvacrol ratios showed bigger inhibition zones for E. coli and L. monocytogenes (20 mm compared with 12.5 mm for lowest to highest carvacrol ratios, respectively). Nanofibers stored at 20 °C (51% RH) showed better retention (40% to 60%) for carvacrol during the first 4 weeks of storage, while nanofibers stored at 2 °C (70% RH) showed better retention (10% to 30%) at the end of storage. Practical Application: Results obtained in the study may help with antimicrobial carvacrol addition levels for gelatin fiber preparation using solution blow spinning (SBS) method. SBS gelatin fibers with added antimicrobials have potential applications for food packaging and medical wound dressing. © 2018 Institute of Food Technologists®

WOS: 000413291700070, PubMed ID: 29037726, Hybrid nanostructures composed of gamma-Fe2O3 (maghemite) and carboxylated-multi walled carbon nanotube (cMWCNT) were used for the magnetic solid phase extractions and determination of Sudan I, II, III, IV, Para Red, Sudan Black B and Sudan Red 7B in chili products. High performance liquid chromatography (HPLC) was employed for the measurements. Limit of quantification (LOQ) values were found in the range 0.44-2.82 ng mL(-1) for analytes. The best extraction parameters were determined as pH 8.0, 40 mg of magnetic nanoparticle, 4.0 min of contact time, 0.3 mL desorption by acetonitrile. The samples were dissolved in acetone-dichloromethane-methanol (3: 2: 1, v/v/v) and diluted with acetonitrile-methanol (v/v; 80: 20) before the method was applied. Concentrations of Sudan dyes and Para Red were determined in four samples of chili powder from less than LOQ to 31.21 +/- 1.6 ng g(-1), two samples of chili tomato sauces (lower than LOQ) and two samples of ketchup (lower than LOQ)., Mardin Artuklu University [MAU-BAP-14-SHMYO-09], The present work was carried out under the financial support of Mardin Artuklu University (MAU-BAP-14-SHMYO-09).

Determination of sugars, especially in fruit juices, is very significant bearing in mind their nutritive importance and the increased demands in food control, especially for fractions of carbohydrates in fresh products. Home-made juices as 'functional food' are in the focus of scientific attention because of the expansion of industrial manufacturing of fruit juices and importance of monoand disaccharides stability for the products quality. In this work determination of content of basic sugars in fruit juices, by applying a high performance liquid chromatography (HPLC), was performed. Content of glucose, fructose and saccharose was analysed in currant, cherry, peach, apricot and strawberry juices as well as in home-made cherry and apricot syrups. Quantification was based on comparison of chromatograms of standard solutions of saccharose, glucose and fructose with our samples. With isocratic elution applied temperature was 90˚C, water as a mobile phase and column Nucleogel Sugar Ca, refractometric detection was applied. The obtained results showed that concentrations of gucose, fructose and saccharose vary in the range 3,149-38,405 g/100 mL, 1,931-30,851 g/100 mL and 0,670-6,072 g/100 mL, respectively. Concerntrations of glucose and fructose do not exhibit significant variations in juices however, they are ten times higher in syrups. In all samples, juices and syrups, concentrations of saccharose do not differ significantly, except for one syrup sample where much lower content could be explained with possible enzymatic decomposition. Određivanje šećera u voćnim sokovima je veoma važno, imajući u vidu njihov nutritivni značaj, ali i povećane zahteve u kontroli hrane kada su u pitanju pojedine frakcije ugljenih hidrata u sveže pripremljenim proizvodima. S obzirom na to da postoji porast industrijske proizvodnje voćnih sokova i značaj stabilnosti monoi disaharida za kvalitet proizvoda, domaći sokovi, kao funkcionalna hrana, postaju sve značajniji. U ovom radu je analiziran sadržaj osnovnih šećera u voćnim sokovima i sirupima kućne izrade primenom visokoefikasne tečne hromatografije (HPLC). Analiziran je sadržaj glukoze, fruktoze i saharoze u sokovima od ribizle, višnje, breskve, kajsije i jagode, kao i u sirupima od višnje i kajsije. Određivanje se zasnivalo na poređenju hromatograma rastvora standarda šećera i naših uzoraka. Uz izokratsko eluiranje analiza je izvođena pri temperaturi od 90 ˚C. Sa vodom kao mobilnom fazom i kolonom Nucleogel Sugar Ca, primenjena je refraktometrijska detekcija. Analizom je pokazano da sadržaj glukoze, fruktoze i saharoze varira u rasponu 3,149-38,405 g/100 ml, 1,931-30,851 g/100 ml i 0,670-6,072 g/100 ml, respektivno. Sadržaj glukoze i fruktoze se ne razlikuje značajno između sokova, a u sirupima je za deset puta veći. Sadržaj saharoze takođe se ne razlikuje značajno među ispitivanim uzorcima, osim u jednom sirupu zbog najverovatnije enzimske razgradnje ovog šećera.

In this study, the presence of genes responsible for the pathogenicity and antibiotic resistance profile of enterococci isolated from various foodstuffs of animal origin was investigated. The percentage prevalence of enterococci was 54.1% (203/375) and the average count was found to be 3.81 log cfu/ml-g. Species-specific primers revealed Enterococcus faecalis as the predominant species carrying one or more virulence-associated traits of efa, gelE, ace, esp and agg genetic markers. Only one E. faecium isolate (from milk) was positive for the esp gene. Regarding antibiotic resistance, the highest frequency of resistance was observed for tetracycline (21.7%), followed by quinupristin/dalfopristin (13.3%), ciprofloxacin (2.0%), penicillin (2.0%), linezolid (1.0%), ampicillin (1.0%), streptomycin (1.0%), and gentamicin (0.5%). Enterococcus faecalis showed a higher prevalence of antibiotic resistance than other enterococci. The percentage of multidrug resistance among the isolates was 3.4%. Twenty-nine E. faecalis isolates (26.6%) carrying one of the virulence-associated traits were at the same time resistant to at least one antibiotic. Our results show that foods of animal origin, including ready-to-eat products, may be reservoirs of antibiotic-resistant and potentially virulent enterococci.

The objective of this study was to determine the prevalence and molecular typing of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in food-producing animals and retail meat in Fargo, North Dakota. A two-step enrichment followed by culture methods were used to isolate S. aureus from 167 nasal swabs from animals, 145 samples of retail raw meat, and 46 samples of deli meat. Positive isolates were subjected to multiplex polymerase chain reaction in order to identify the genes 16S rRNA, mecA, and Panton-Valentine Leukocidin. Pulsed-field gel electrophoresis and multilocus sequence typing were used for molecular typing of S. aureus strains. Antimicrobial susceptibility testing was carried out using the broth microdilution method. The overall prevalence of S. aureus was 37.2% (n = 133), with 34.7% (n = 58) of the animals positive for the organism, and the highest prevalence observed in pigs (50.0%) and sheep (40.6%) (p < 0.05); 47.6% (n = 69) of raw meat samples were positive, with the highest prevalence in chicken (67.6%) and pork (49.3%) (p < 0.05); and 13.0% (n = 6) of deli meat was positive. Five pork samples (7.0%) were positive for MRSA, of which three were ST398 and two were ST5. All exhibited penicillin resistance and four were multidrug resistant (MDR). The Panton-Valentine Leukocidin gene was not detected in any sample by multiplex polymerase chain reaction. The most common clones in sheep were ST398 and ST133, in pigs and pork both ST398 and ST9, and in chicken ST5. Most susceptible S. aureus strains were ST5 isolated from chicken. The MDR isolates were found in pigs, pork, and sheep. The presence of MRSA, MDR, and the subtype ST398 in the meat production chain and the genetic similarity between strains of porcine origin (meat and animals) suggest the possible contamination of meat during slaughtering and its potential transmission to humans. College of Agriculture, Food Systems and Natural Resources College, North Dakota State University College of Veterinary Medicine, Iowa State University

Sulfapyridine (SPy) is a sulfonamide antibiotic largely employed as veterinary drugs for prophylactic and therapeutic purposes. Therefore, its spread in the food products has to be restricted. Herein, we report the synthesis and characterization of a novel electrochemical biosensor based on gold microelectrodes modified with a new structure of magnetic nanoparticles (MNPs) coated with poly(pyrrole-co-pyrrole-2-carboxylic acid) (Py/Py-COOH) for high efficient detection of SPy. This analyte was quantified through a competitive detection procedure with 5-[4-(amino)phenylsulfonamide]-5-oxopentanoic acid-BSA (SA2-BSA) antigens toward polyclonal antibody (Ab-155). Initially, gold working electrodes (WEs) of integrated biomicro electro-mechanical system (BioMEMS) were functionalized by Ppy-COOH/MNPs, using a chronoamperometric (CA) electrodeposition. Afterward, SA2-BSA was covalently bonded to Py/Py-COOH/MNP modified gold WEs through amide bonding. The competitive detection of the analyte was made by a mixture of a fixed concentration of Ab-155 and decreasing concentrations of SPy from 50µgL-1 to 2ngL-1. Atomic Force Microscopy characterization was performed in order to ensure Ppy-COOH/MNPs electrodeposition on the microelectrode surfaces. Electrochemical measurements of SPy detection were carried out using electrochemical impedance spectroscopy (EIS). This biosensor was found to be highly sensitive and specific for SPy, with a limit of detection of 0.4ngL-1. This technique was exploited to detect SPy in honey samples by using the standard addition method. The measurements were highly reproducible for detection and interferences namely, sulfadiazine (SDz), sulfathiazole (STz) and sulfamerazine (SMz). Taking these advantages of sensitivity, specificity, and low cost, our system provides a new horizon for development of advanced immunoassays in industrial food control.

In this work, the role of in situ exopolysaccharide (EPS) production under different fermentation conditions on physicochemical, microbiological, textural and microstructural properties of sucuk was determined. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 14, 16 and 18 C and time; 8, 12 and 16 days) on physicochemical, microbiological, textural and microstructural properties were investigated using response surface methodology. In situ EPS production was observed to remarkably affect these properties while fermentation conditions were also seen to dominantly influence the physicochemical properties of sucuk, revealing that the ripening temperature appeared to be more determinant factor. EPS producing cultures enhanced the textural properties of sucuk which became harder, less adhesive and tougher. The microstructural analysis revealed the formation of web -like structure by in situ EPS production in sucuk mix during fermentation process. This study revealed the importance of in situ EPS production on final technological properties of sucuk. (C) 2016 Elsevier Ltd. All rights reserved.

© 2015 Elsevier Ltd. Acrylamide formation during the production of French fries is attributed to Maillard reactions from reducing sugars and asparagine and is dependent on the frying temperature. Low reducing sugars content in potatoes has been recommended to produce fried potato products. However, the influence of the complexity of the potato medium in the chemical reactions that promote the acrylamide formation during deep frying are not well understood. In this study, three potato cultivars (Kennebec, Red Pontiac and Agria) commonly used for fried potato products were evaluated to determine the relationships between the precursors of acrylamide in the fresh potato tubers and the properties of the fried potato strips with the acrylamide content after frying. Frying experiments were conducted at three conditions (time-temperature) to obtain French fries of similar visual colour. Acrylamide formation increased with frying temperature but different behaviour was observed between cultivars. For Red Pontiac, a remarkably increase in acrylamide content was found at 170 °C (~40%) together with the increase in colour. However, lower oil uptake and higher moisture content was obtained as temperature increase. Significant positive correlations were observed between the acrylamide level and the reducing sugars and sucrose content on fresh potatoes (0.652, 0.699, p = 0.01, respectively). The acrylamide content obtained in Agria cultivar may be obtained from the hydrolysis of sucrose during the frying process. In fried potato strips, positive significant correlation was found between the shear force and acrylamide (0.749, p = 0.01). The significant correlations obtained between colour, and texture, colour and oil uptake and texture and acrylamide content indicate the intrinsic relationship between the properties of the fried potato strips and the acrylamide content.

Subtilisin was immobilized on polycaprolactam and used for food packaging applications to reduce the transference of microorganisms from the packaging material to the packaged food material. The optimized conditions for subtilisin immobilization was as follows: pH, 8; temperature, 4 �C; glutaraldehyde, 0.5%; incubation time, 25 h; and subtilisin concentration, 600 ?L. The formation of -CH=N- at 1576 cm -1 in the Fourier transform infrared (FTIR) spectrum confirmed the immobilization. Subtilisin-immobilized polycaprolactam (SIP) exhibited the highest residual activity of 106.67 � 4.41% and 104.67 � 0.88% at 40 �C and pH 8 and retained residual activity of 94% at the end of 56 days when compared to 21.33 � 4.10% in the case of free subtilisin. SIP significantly (p < 0.05) lowered the colony forming units (CFU), dry weight, and protein and carbohydrate contents in bacterial and fungal biofilm. Practical application of the SIP on ham steaks at 4 and 20 �C showed a 2-3 times reduction of Staphylococcus aureus as well as Escherichia coli cells in the range of p < 0.05. � 2011 American Chemical Society.

Direct infusion electrospray ionization tandem mass spectrometry in the negative ion mode with single reaction monitoring is show to allow high selectivity and sensitivity in the quantification of taurine in energetic drinks. The method is also simple and rapid (less than 2 min run time), with high recovery and repeatability. Commercially available energetic drinks were found to contain taurine in concentrations quite different (lower or higher) from the declared amounts. Espectrometria de massas sequencial usando infusão direta de amostra e ionização por electrospray no modo de ions negativos foi utilizada para quantificar taurina em bebidas energéticas com alta seletividade e sensibilidade, O metodo é simples e rápido (menos de 2 min de corrida) e apresenta alta repetitividade e recuperação. Bebidas energéticas comerciais apresentaram quantidades de taurina em concentrações muito diferentes (menor ou maior) das quantidades declaradas.

The physicochemical properties of tarhana soup produced with different dough treatments, fermentation times, and preservation methods were examined. Tarhana doughs were prepared with yogurt (control) or baker's yeast (Saccharomyces cerevisiae) and fermented for 3 days. Samples were taken at 24, 48, and 72 hr. Samples were then preserved via one of four methods: sun dried, dried in the shade, vacumn dried, and frozen. Frozen samples produced lower organic acid levels after 72 hr of fermentation in both control (0.68 g/100 g) and yeast (0.61 g/100 g) applications than samples that were dried (0.94 g/100 g control samples; 0.81 g/100 g samples with yeast). Increasing fermentation time resulted in a significant effect on the formation of organic acid in the tarhana (p.01). At 72 hr of fermentation, total acidity increased 11%, 17%, and 23% for tarhana samples vacumn-dried, sun-dried, and dried in the shade, respectively. Preservation methods also affected the moisture, ash, crude protein, total acidity, pH, salt, fat, reducing sugar levels, and the sensory assestment of tarhana soup (p.01). Sensory characteristics were not significantly affected by baker's yeast in any of the preservation methods used (p.01). However, sensory scores for tarhana prepared from the samples dried in a sheltered area showed a reduction in color desireablilty as the fermentation time increased. The soup prepared from frozen tarhana (72 hr fermentation, with yeast) had the highest scores with respect to color, mouth feel, flavor, and overall acceptability. Vacuum-dried samples' scores in these areas were also high in comparison to the two other drying methods.

Debaryomyces nepalensis NCYC 3413, a food spoiling yeast isolated from rotten apple, has been previously demonstrated as halotolerant yeast. In the present study, we assessed its growth, change in cell size, and measured the intracellular polyol and cations (Na(+) or K(+)) accumulated during growth in the absence and presence of different concentrations of salts (NaCl and KCl). Cells could tolerate 2 M NaCl and KCl in defined medium. Scanning electron microscopic results showed linear decrease in mean cell diameter with increase in medium salinity. Cells accumulated high amounts of K(+) during growth at high concentrations of KCl. However, it accumulated low amounts of Na(+) and high amounts of K(+) when grown in the presence of NaCl. Cells grown in the absence of salt showed rapid influx of Na(+)/K(+) on incubation with high salt. On incubation with 2 M KCl, cells grown at 2 M NaCl showed an immediate efflux of Na(+) and rapid uptake of K(+) and vice versa. To withstand the salt stress, osmotic adjustment of intracellular cation was accompanied by intracellular accumulation of polyol (glycerol, arabitol, and sorbitol). Based on our result, we hypothesize that there exists a balanced efflux and synthesis of osmolytes when D. nepalensis was exposed to hypoosmotic and hyperosmotic stress conditions, respectively. Our findings suggest that D. nepalensis is an Na(+) excluder yeast and it has an efficient transport system for sodium extrusion.

The aim of this study was to use molecular techniques to assess the microbiota of eight raw cow's milk samples at biotype and species level. Sixty-six isolates from raw milk samples were screened by Randomly amplified polymorphic DNA-PCR (RAPD-PCR) biotyping and representative strains of RAPD-PCR profiles were identified by 16S rRNA gene sequencing. Pseudomonas spp. were the most commonly occurring contaminants along with Enterobacteriaceae such as Hafnia alvei, Serratia marcescens and Citrobacter freundii. Moreover, Gram-positive isolates belonging to the genera Staphylococcus and Lactococcus were also found. Experiments of growth at different temperatures showed that more than 50% of the Gram-negative isolates could grow at chill temperatures and that 65% of the Pseudomonas spp. strains grew at 7 degrees C within 5 days. Only 13 Gram-negative isolates displayed proteolytic activity on milk agar, suggesting that not all the biotypes of milk contaminating species are able to perform this spoilage-associated activity. Among the Gram negative, the proteolytic strains were mainly Peudomonas spp. that displayed the activity at both 7 degrees C and 20 degrees C. A reliable molecular identification of raw milk microbiota is important for the study of the microbiological quality of raw milks and for the assessment of the ecology at species level in order to develop improved systems, preventing contamination and having the best conditions for the storage of milk.

A reliable method for the determination of patulin in apple juice, apple puree and apples was developed using two clean-up steps and high performance liquid chromatography and diode array (HPLC-DAD) analysis. Baseline separation from hydroxymethyl furfural (HMF) was obtained. The performance characteristics of the method were determined at four concentration levels in two matrices and fulfill the requirements of the European Commission (EC) for this type of samples. The level of quantification was set to 25 μg/l or 25 μg/kg, the RSD for repeatability at this level is 11% for apple juice and 17% for apples, the recovery is 87% for apple juice and 63% for apples. The reproducibility was determined in apples and is 11% (at a level of 200 μg/kg). The method was used for determination of patulin in 63 commercial apple products available on the Dutch market. With the exception of one sample, the level of patulin was lower than the detection limit in all the samples. No statistically significant difference was found between conventional and organic samples. © 2004 Elsevier Ltd. All rights reserved.

Ozalp, Veli Cengiz/0000-0002-7659-5990; WOS:000345652000055 PubMed: 25467500 A quartz crystal microbalance sensor (QCM) was developed for sensitive and specific detection of Salmonella enterica serovar typhimurium cells in food samples by integrating a magnetic bead purification system. Although many sensor formats based on bioaffinity agents have been developed for sensitive and specific detection of bacterial cells, the development of robust sensor applications for food samples remained a challenging issue. A viable strategy would be to integrate QCM to a pre-purification system. Here, we report a novel and sensitive high throughput strategy which combines an aptamer-based magnetic separation system for rapid enrichment of target pathogens and a QCM analysis for specific and real-time monitoring. As a proof-of-concept study, the integration of Salmonella binding aptamer immobilized magnetic beads to the aptamer-based QCM system was reported in order to develop a method for selective detection of Salmonella. Since our magnetic separation system can efficiently capture cells in a relatively short processing time (less than 10 min), feeding captured bacteria to a QCM flow cell system showed specific detection of Salmonella cells at 100 CFU mL(-1) from model food sample (i.e., milk). Subsequent treatment of the QCM crystal surface with NaOH solution regenerated the aptamer-sensor allowing each crystal to be used several times. (C) 2014 Elsevier B.V. All rights reserved.

The suitable properties of potential probiotic lactic acid bacteria (LAB) strains (preselected among 153 strains on the basis of their potential technological properties) isolated from traditional Çubuk pickles were examinedin vitro. For this purpose, these strains (21Lactobacillus plantarum, 11Pediococcus ethanolidurans,and 7Lactobacillus brevis) were tested for the ability to survive at pH 2.5, resistance to bile salts, viability in the presence of pepsin-pancreatin, ability to deconjugate bile salts, cholesterol assimilation, and surface hydrophobicity properties. Most of the properties tested could be assumed to be strain-dependent. However,L. plantarumandL. brevisspecies were found to possess desirable probiotic properties to a greater extent compared toP. ethanolidurans. In contrast toP. ethanoliduransstrains, the testedL. plantarumandL. brevisstrains exhibited bile salt tolerance, albeit to different extent. All tested strains showed less resistance to intestinal conditions than gastric juice environment. Based on the survival under gastrointestinal conditions, 22 of the 39 strains were selected for further characterization. The eight strains having the highest cholesterol assimilation and surface hydrophobicity ratios could be taken as promising probiotic candidates for furtherin vivostudies, because of the strongest variations found among the tested strains with regard to these properties.

Analysis of residual levels of tetracyclines (TCs) in chicken meat was performed using a validated liquid chromatography coupled with a tandem mass spectrometry (LC-MS/MS) technique. Overall, the recoveries for TCs ranged from 56.9% to 101.2%, with standard deviations of 4.5-13.2%. Detection limits ranged from 7.9 to 14.6 mu g kg(-1). In four of 60 samples, doxycycline (DXC) was determined in a range from 19.9 to 35.6 mu g kg(-1); and in one sample tetracycline was detected at 17.2 mu g kg(-1). Chlortetracycline (CTC) and oxytetracycline (OTC) were not detected in any of the tested samples. This study indicates that chicken meat sold in Bursa, Turkey, contained some residues of TCs. Therefore, stricter regulations for the use of antibiotics in the poultry industry and the monitoring of drug residues in chicken meat prior to marketing are needed. Finally, this method has been applied successfully for the confirmation of TCs in chicken meat.

Hydrogen sulfide (H2S) is a powerful aroma compound largely produced by yeast during fermentation. Its occurrence in wines and other fermented beverages has been associated with off-odors described as rotten egg and/or sewage. While the formation of hydrogen sulfide (H2S) during fermentation has been extensively studied, it is the final H2S content of wine that is actually linked to potential off-odors. Nevertheless, factors determining final H2S content of wine have received little attention, and it is commonly assumed that high H2S-forming fermentations will result in high final concentrations of H2S. However, a clear relationship has never been established. In this report, we investigated the contribution of yeast strain and nitrogen addition to H2S formation during fermentation and its consequent occurrence the resulting wines. Five commercial Saccharomyces cerevisiae wine yeast strains were used to ferment a Chardonnay juice containing 110 mg/l of YAN (yeast assimilable nitrogen), supplemented with di-ammonium phosphate (DAP) to increase YAN concentration to moderate (260 mg/l) and high (410 mg/l) levels. In contrast to the widely reported decrease in H2S production in response to DAP addition, a non-linear relationship was found such that moderate DAP supplementation resulted in a remarkable increase in H2S formation by each of the five wine yeasts. H2S content of the finished wine was affected by yeast strain, YAN, and fermentation vigor. However, we did not observe a correlation between concentration of H2S in the finished wines and H2S produced during fermentation, with low-forming fermentations often having relatively high final H2S and vice versa. Management of H2S in wine through nitrogen supplementation requires knowledge of initial YAN and yeast H2S characteristics.

This work describes the correlation found along 10 days between potentiometric measurements obtained by using an electronic tongue and the variation in certain physicochemical, microbial and biochemical parameters measured on a whole piece of pork loin stored under refrigeration. The electronic tongue consists of a set of six electrodes made of Au, Ag, Cu, Pb, Zn and C, and a reference electrode. Through the use of various multivariate analysis techniques, such as: PCA and two types of artificial neural networks (i.e. multilayer perceptron (MLP) and fuzzy ARTMAP) it was found that it is possible to determine the time elapsed in relation to the degradation of the loin by using simple potentiometric measurements. Additionally, in the same pork sample used to measure redox potentials with the electronic tongue, the following parameters were also determined; pH, microbial count, concentrations of inosine 5'-monophosphate (IMP), inosine (Ino) and hypoxanthine (Hx). Through the use of PLS analysis, it was found a rather good correlation between pH and the potentiometric data. Also a remarkable correlation was observed between the measures carried out with the electronic tongue and the so-called K-index that simultaneously measures the variation in the adenosine triphosphate (ATP) degradation products. These results suggest that this simple, or a similar electronic tongue, could be useful for the undemanding qualitative or semi-quantitative evaluation of freshness in meat samples in a wide range of situations. © 2010 Elsevier Ltd. All rights reserved., We would like to thanks the Spanish Government for support (Project CTQ2006-15456-C04-01/BQU and AGL2007-65379-C02-01 and 02/ALI). This work has been partially carried out under Associated Unit framework between IIAD (UPV) and IATA (CSIC).

Bu çalışmada, eser düzeydeki Sn(IV) iyonlarının alevli atomik spektrometri ile tayini için yeni bir bulutlanma noktası ekstraksiyon(CPE) yöntemi geliştirildi. Geliştirilen yöntemde Sn(IV) iyonları kalkon karboksilik asit(CCA) ligantı ile kompleksleştirilip, katyonik surfaktan setil piridinyum klorür(CPC) içeren ortamda ekstrakte edilmiştir. Surfaktan derişimi, reaktif derişimleri, pH ve zamanın etkisi gibi ekstraksiyon ve tepkime koşulları optimize edilerek, tayin sınırı, doğrusal aralık ve zenginleştirme faktörü gibi analitik özellikler belirlenmiştir.Optimum koşullar altında bulunan doğrusal çalışma aralığı 10.0 - 1300.0 µg L-1 Sn(IV) (8.4 × 10-8 - 1.1 × 10-5 mol L-1) , tayin sınırı ise 2.86 µg L-1 Sn(IV) (2.4 × 10-8 mol L-1) olarak bulunmuştur. 50.00 µg L-1 Sn(IV) derişimi için bulunan bağıl standart sapma ve 10 tekrarlı ölçümden bulunan bağıl hata sırasıyla %0.92 ve %2.9 iken aynı değerler 500.0 µg L-1 Sn(IV) için %0.72 ve %1.4 dür. Önerilen yönteme çeşitli anyon ve katyonların girişim etkileri araştırılmıştır. Geliştirilen yöntem bazı çevresel su örnekleri, konserve gıdalar ve bazı içecek türlerindeki Sn türlerinin tayine uygulanmıştır. Ayrıca önerilen yöntemin doğruluğu, su örnekleri üzerinde yapılan geri kazanım çalışmaları ve sertifikalı su örnekleri ile karşılaştırma deneyleri ile test edilmiş ve sonuçların sertifikalı değerlere uyum içinde olduğu görülmüştür. A micelle-mediated phase preconcentration of trace quantities of Sn(IV) for determination by flame atomic absorption spectrophotometry has been developed, based on cloud point extraction (CPE) of the complex of Sn(IV) with calcon carboxylic acid complex in surfactant media. Calcon carboxylic acid (CCA) and cetylpyridinium chloride (CPC) were used as chelating agent and cationic surfactant, respectively. The optimal extraction and reaction conditions (e.g. surfactant concentration, reagent concentration and the effects of pH and time) were studied and the analytical characteristics of the method (e.g., limit of detection, linear range and preconcentration factor) were determined.A calibration curve was obtained has linear range between 10.0 µg L-1 and 1300.0 µg L-1 (8.4 × 10-8 to 1.1 × 10-5 mol L-1). The detection limit (LOD) of the method was 2.86 µg L-1 (2.4 × 10-8 mol L-1) of Sn(IV). The relative standard deviation (R.S.D.) and relative error for five replicates of 50.00 µg L-1 Sn(IV) were 0.92% and 2.9%, and for 500.00 µg L-1 of Sn(IV) were 0.72% and 1.4%, respectively. The interference effect of some anions and cations was also investigated. The method was applied to the determination of tin in soft drinks and canned foods and water samples, with satisfactory results. The proposed method was applied to the speciation of tin in different water samples and the recoveries in the range of 98.9?105.3% were obtained by spiking the real samples. In order to verify the accuracy of the method, a certified reference water sample was analyzed and the results obtained were in good agreement with the certified values. 74

Quorum sensing (QS) is a signalling mechanism through which bacteria cellular functions are modified to promote access to nutrients and more favorable environmental niches. The frequent occurrence of Pseudomonas spp. in fresh and spoiled meat may involve enhanced gene expression regulated by QS. Several Pseudomonas spp. produce different N-acyl homoserine lactone (AHL) signal molecules. Meat spoilage during aerobic, refrigerated storage is often associated with the presence of Pseudomonas fragi. As with other Pseudomonas species in natural habitats, the dominance and activities of P. fragi in meat may be regulated by QS. In this study, five biosensor strains were used to detect AHL production on three different media by 72 different P. fragi strains isolated from fresh and spoiled meat. Positive and negative AHL-producing strains were used to verify the assays. None of the strains produced detectable quantities of AHLs, even when concentrated cell-free culture supernatants were assayed, nor did exogenous lactones increase biofilm formation in P. fragi strains. However, all isolates produced furanosyl borate diesters (type II autoinducers; AI-2) when tested using the bioluminescent biosensor strain of Vibrio harveyi (BB170). The production of AI-2 was presumed to be of metabolic origin even though Pseudomonas spp. have not been shown to harbor the luxS gene. Thus, the efficient development of P. fragi in fresh meat is not regulated by an AHL-mediated QS system. The mechanism of AI-2 production and its possible role in spoilage dynamics needs further study.

The poor precision of the "percentage of discarded fruits" and "Howard mold count" methods has increased the importance of ergosterol for the microbiological quality evaluation of tomato and tomato products. Ergosterol, a constituent of the cell wall of some important vegetable parasites, such as molds, has been recently recognized as a potential objective parameter useful for the characterization of the quality of processing tomatoes. Thus, 15 mg of ergosterol/kg total solids has been stated as an acceptability maximum limit of tomato products. C1 Pamukkale Univ, Fac Engn, Dept Food Engn, TR-20020 Camlik Denizli, Turkey. Ankara Univ, Fac Agr, Dept Food Engn, TR-06100 Ankara, Turkey.

Microbial interaction can be ignored in predictive microbiology under most conditions. We show that interactions are only important at high population densities, using published data on inhibition of growth of Listeria monocytogenes in broth. Our analysis using growth models from predictive microbiology indicated that interactions only occur at population densities of ∼108 cfu/ml of the protective cultures. Spoilage is evident at these levels, except for fermented foods. In bacterial colonies, diffusion limitation acts as a constraint to growth. We have shown that these constraints only become important after large outgrowth of colonies (in the order of 5-log growth in Lactobacillus curvatus colonies), which depends on the initial inoculation density. Intra-colony interactions play an important role under these conditions. There is no large outgrowth of colonies when the initial inoculation densities are high and broth culture growth can be used to approximate colony growth. © 2002 Elsevier Science B.V. All rights reserved. Chemicals/CAS: Culture Media

Lactobacillus species (183 strains) isolated during the ripening of soppressata molisana, a typical fermented sausage from Molise, were characterized. Of these isolates the large majority (125 strains) was classified as Lactobacillus sake . Few strains were obligately heterofermentative and were identified as Lb. brevis . All strains were able to grow in the presence of 8% NaCl and a large majority was able to grow in the presence of 10% NaCl. No strains were able to hydrolyse pork fat at 18°C. Several isolates were H 2 O 2 and acetoin producers. Few strains were responsible for slime production. All the isolates also showed high resistance to nitrites.

An experimental study was carried out to establish whether the draft EEC method for the determination of the global migration of constituents from plastics packaging materials into fatty food stimulants could be applied to all plastics, including lacquers and laminates. Some difficulties were encountered in the use of the EEC method for melamine, for hotmelt-coated packaging materials and for laminates containing one or more layers of materials sensitive to moisture, such as paper, cardboard or regenerated cellulose film. Chemicals/CAS: cellulose, 61991-22-8, 68073-05-2, 9004-34-6; melamine, 108-78-1, 25778-04-5; Dietary Fats; Plastics

Samples of barley, wheat and maize were analysed for deoxynivalenol (DON). Samples were extracted with aqueous chloroform-ethanol. The extract was purified by column chromatography on silica gel. DON was derivatised with heptafluorobutyric (HFB) acid anhydride. The glassware was silylated to prevent deterioration of the HFB derivative, which stabilised the samples for at least 11 weeks. Quantitation was done by capillary gas chromatography using electron-capture detection. Confirmation was obtained by gas chromatography-mass spectrometry. The limit of determination was 0.02 mg/kg. Recoveries of DON averaged 99% with a coefficient of variation of 10.8%. ?? 1986 Springer-Verlag. Chemicals/CAS: vomitoxin, 51481-10-8; deoxynivalenol, 51481-10-8; Sesquiterpenes; Trichothecenes

Growing microorganisms on dry surfaces, which results in exposure to low water activity (aw), may change their normal morphology and physiological activity. In this study, the morphological changes and cell viability of Salmonella enterica serovar Enteritidis challenged to low a w were analyzed. The results indicated that exposure to reduced aw induced filamentation of the cells. The amount of filamentous cells at aw 0.94 was up to 90% of the total number of cells. Surviving filamentous cells maintained their membrane integrity after exposure to low aw for 21 days. Furthermore, cells prechallenged to low a w, obtained with an ionic humectant, demonstrated higher resistance to sodium hypochlorite than control cells. These resistant cells are able to survive disinfection more efficiently and can therefore cause contamination of foods coming in contact with surfaces. This points to the need for increased attention to cleaning of surfaces in household environments and disinfection procedures in processing plants. Copyright ©, International Association for Food Protection.

Background Both O157 and non-O157 Shiga toxin - producing Escherichia coli (STECs) cause serious human disease outbreaks through the consumption of contaminated foods. Cattle are considered the main reservoir but it is unclear how STECs affect mature animals. Neonatal calves are the susceptible age class for STEC infections causing severe enteritis. In an earlier study, we determined that mycotoxins and STECs were part of the disease complex for dairy cattle with Jejunal Hemorrhage Syndrome (JHS). For STECs to play a role in the development of JHS, we hypothesized that STEC colonization should also be evident in beef cattle with JHS. Aggressive medical and surgical therapies are effective for JHS, but rely on early recognition of clinical signs for optimal outcomes suggesting that novel approaches must be developed for managing this disease. The main objective of this study was to confirm that mouldy feeds, mycotoxins and STEC colonization were associated with the development of JHS in beef cattle. Results Beef cattle developed JHS after consuming feed containing several types of mycotoxigenic fungi including Fusarium poae, F. verticillioides, F. sporotrichioides, Penicillium roqueforti and Aspergillus fumigatus. Mixtures of STECs colonized the mucosa in the hemorrhaged tissues of the cattle and no other pathogen was identified. The STECs expressed Stx1 and Stx2, but more significantly, Stxs were also present in the blood collected from the lumen of the hemorrhaged jejunum. Feed extracts containing mycotoxins were toxic to enterocytes and 0.1% of a prebiotic, Celmanax Trademark, removed the cytotoxicity in vitro. The inclusion of a prebiotic in the care program for symptomatic beef calves was associated with 69% recovery. Conclusions The current study confirmed that STECs and mycotoxins are part of the disease complex for JHS in beef cattle. Mycotoxigenic fungi are only relevant in that they produce the mycotoxins deposited in the feed. A prebiotic, Celmanax Trademark, acted as a mycotoxin binder in vitro and interfered with the progression of disease.