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Low glycemic index (GI) diets have been associated with decreased chronic disease risk. In a randomized, cross-over study we investigated the GI and glycemic response to three traditional Greek mixed meals: Lentils, Trahana, and Halva. Twelve healthy, fasting individuals received isoglucidic test meals (25 g available carbohydrate) and 25 g glucose reference, in random order. GI was calculated and capillary blood glucose (BG) samples were collected at 0–120 min after meal consumption. Subjective appetite ratings were assessed. All three tested meals provided low GI values. Lentils GI was 27 ± 5, Trahana GI was 42 ± 6, and Halva GI was 52 ± 7 on glucose scale. Peak BG values were lowest for Lentils, followed by Trahana and then by Halva (p for all

Salmonella spp. is known to survive in intermediate– and low–moisture foods. Bakery products such as cream-filled brioche (aw 0.82–0.84), depending mainly on the aw of the fillings and the baking they receive for food preservation, may support survival of the pathogen. The study aimed to model the inactivation of osmotically adapted and non–adapted Salmonella in cream–fillings (praline and biscuit) and cream-filled brioche at different storage temperatures. All matrices were inoculated with ca. 6.0 log CFU/g of osmotically adapted and non–adapted five–strain cocktail of Salmonella (Typhimurium, Agona, Reading, and Enteritidis) and stored aerobically in 120 mL screw-capped containers at 15, 20, and 30 °C. Adaptation of Salmonella was induced in cream–fillings (praline and biscuit) with aw adjusted to 0.88, by adding sterile water to each of the original fillings (aw 0.78–0.83) and incubating at 37 °C for 1 h. Survival of Salmonella was assessed at regular time intervals throughout storage using thin layer agar method to enhance the recovery of injured cells (n = 4). Inactivation curves were fitted best with the Weibull model using the freeware GInaFit tool and the estimated δ and β values were used to calculate the time for 4D reduction–t4D. Results showed that inactivation of Salmonella increased with temperature, while osmotic adaptation enhanced its survival in a food matrix–related manner. Higher survival rates of adapted cells were observed in cream–fillings (t4D: 79.9 ± 27.1 days on biscuit and 150.3 ± 19.6 days on praline) compared to brioche (t4D: 61.3 ± 0.9 days on biscuit and 52.5 ± 4.6 days on praline) at 20 °C. Secondary (linear) modelling of t4D showed that the survival of Salmonella was affected by temperature and osmotic adaptation. Model simulation of pathogen inactivation in independent trials on cream–fillings agreed well with observed data. In conclusion, the present data could be used as a means to identify areas for improving the performance of existing models quantifying the survival of Salmonella in bakery-confectionary products with intermediate aw.

The scope of the present study was to assess the spoilage potential of different Alicyclobacillus spp. in commercial pasteurized (ambient-stable) plant-based dairy beverages mixed with fruit juices at different inoculation levels and storage temperatures. Different products (coconut and berry [CB]; almond, mango, and passionfruit [AMP]; and oat, strawberry, and banana [OSB]) were inoculated with 10 or 2 × 103 spores per mL of either Alicyclobacillus acidoterrestris, Alicyclobacillus fastidiosus, or Alicyclobacillus acidocaldarius strain composites, whereas noninoculated samples served as controls. Samples inoculated with A. acidoterrestris and A. fastidiosus were stored at 30 and 45°C, whereas A. acidocaldarius storage took place at 50°C for 240 days. Gas composition, Alicyclobacillus spp. populations, total viable counts, pH, water activity, color, and guaiacol off-taste were monitored. CB and AMP supported growth of A. acidoterrestris and A. fastidiosus, reaching populations of 4.0 to 5.0 log CFU/mL. In OSB, populations of A. fastidiosus remained close to the initial inoculation levels during storage at 30°C, whereas at 45°C, the populations declined

The coexistence and interactions among Listeria monocytogenes strains in combination with the structural characteristics of foods, may influence their growth capacity and thus, the final levels at the time of consumption. In the present study, we aimed to evaluate the effect of oxygen availability in combination with substrate micro-structure on growth and inter-strain interactions of L. monocytogenes. L. monocytogenes strains, selected for resistance to different antibiotics (to enable distinct enumeration), belonging to serotypes 4b (C5, ScottA), 1/2a (6179) and 1/2b (PL25) and were inoculated in liquid (Tryptic Soy Broth supplemented with Yeast Extract — TSB-YE) and solid (TSB-YE supplemented with 0.6% and 1.2% agar) media (2–3 log CFU/mL, g or cm2), single or as two-strain cultures (1:1 strain-ratio). Aerobic conditions (A) were achieved with constant shaking or surface inoculation for liquid and solid media respectively, while static incubation or pour plated media corresponded to hypoxic environment (H). Anoxic conditions (An) were attained by adding 0.1% w/v sodium thioglycolate and paraffin overlay (for solid media). Growth was assessed during storage at 7 °C (n = 3 × 2). Inter-strain interactions were manifested by the difference in the final population between singly and co-cultured strains. Τhe extent of suppression increased with reduction in agar concentration, while the impact of oxygen availability was dependent on strain combination. During co-culture, in liquid and solid media, 6179 was suppressed by C5 by 4.0 (in TSB-YE under H) to 1.8 log units (in solid medium under An), compared to the single culture, which attained population of ca. 9.4 log CFU/mL or g. The growth of 6179 was also inhibited by ScottA by 2.7 and 1.9 log units, in liquid culture under H and An, respectively. Interestingly, in liquid medium under A, H and An, ScottA was suppressed by C5, by 3.3, 2.4 and 2.3 log units, respectively, while in solid media, growth inhibition was less pronounced. Investigating growth interactions in different environments could assist in explaining the dominance of L. monocytogenes certain serotypes.

The objectives of the study were to evaluate: (i) the efficacy of Na-alginate films immersed in 40% v/v distillery ethanol and traditional Greek alcoholic beverages (ABs), namely “tsipouro”, “raki”, and “ouzo” to inhibit Listeria monocytogenes growth on frankfurters and ham slices and (ii) the impact of edible films-ABs on heat sensitivity of the pathogen after microwave (MW) reheating of frankfurters in water during storage at 4 and 10 °C. Samples without edible films (controls) or with edible films but free of distillery ethanol or ABs were also tested. Two pieces of frankfurters were placed between two edible films, while every ham slice was covered by a film from both sides. On ham, all edible films immersed in ABs maintained levels of L. monocytogenes at least 5.0 log CFU/cm 2 lower (p L. monocytogenes population remained 4.0–4.5 log CFU/cm 2 lower (p 2 was observed after 15 days at 10 °C, at all assays except for samples packaged with raki. However, the results from reheating experiments revealed that subsequent inadequate MW reheating of frankfurters packaged with edible films-ABs would not lead to remarkable inactivation of the pathogen, since cross-protection against thermal stress is been acquired as a result of products' exposure to sub-lethal stresses such as low pH formed by metabolic products, indigenous microbiota, and ethanol exposure ( ca. 2.4–2.7% w/w) during cold storage. Our findings suggest that food safety regulations enabling antimicrobial interventions for the safety of ready to eat meat products should ensure both low levels of L. monocytogenes during storage and minimum tolerance to recommended consumer practices, such as MW reheating.

The present study aimed to develop a commercial active packaging system of ground beef, by exploiting the antimicrobial and antioxidant properties of a traditional Greek alcoholic distillate called &ldquo, tsipouro&rdquo, Commercial packages (500 g) were used and 40 mL of &ldquo, was added in absorbent pads placed underneath the ground beef, while 10 mL was also mounted under the packaging film, facing the headspace. Samples were packaged in 80% O2: 20% CO2 and stored at 0, 4, 8, and 12 &deg, C. Total Viable Counts, pseudomonads, Brochothrix thermosphacta, lactic acid bacteria, yeasts-moulds, pH, colour (L*, a*, b*), odour (buttery and acidic), and ethanol migration to ground beef (SPME/GC-FID) were determined. Moreover, mathematical models (square root and Arrhenius) describing the effect of temperature on determinant indicators of spoilage and quality deterioration like growth of dominant microorganisms and red colour reduction were developed and validated under non-isothermal conditions. B. thermosphacta dominated the microbial association of ground beef, while LAB were second in dominance, revealing a high growth potential at all assays. a* value (redness) was gradually decreased in controls, while samples treated with &ldquo, showed more stable red colour during storage. Although ethanol was organoleptically detectable, especially at low storage temperatures (0&ndash, 4 &deg, C), it was rather perceived as a pleasant cool odour. Prediction by both models for microbial growth as well as those of Arrhenius model for reduction of a* value showed good agreement with the observations under non-isothermal storage. Overall, our study showed that the developed antimicrobial active packaging of ground beef based on &ldquo, combined with high oxygen MAP lead to an almost 2-fold shelf-life extension compared with controls during storage at chill and abuse temperatures.

The scope of the present study was to use selected fruits as model foods (wounded skin or slices of apples and pears), for the in situ assessment of the potential of natural antimicrobials to control fungal growth and OTA production and the investigation of alternative ways of their application, e.g., via edible coatings. Fresh fruits were cut: i) in halves or ii) across in round slices of ca. 1 cm thickness. Wounds were introduced into the skin and the center of the slice (5 mm deep; 4 mm diameter) and inoculated with a range of 2.0–7.5 × 103spores per wound of Aspergillus carbonarius. Following inoculation, samples were coated with Na – alginate supplemented with 0.3 (0.3% ECC) and 0.9% v/v (0.9% ECC) cinnamon EΟ. Inoculated samples without edible coating and EO (C) or with edible coating and without EO (EC) were used as negative or positive controls, respectively. All samples were stored under aerobic conditions at 15, 20, and 25 °C. Fungal growth was estimated by colony diameter measurements (n = 30), while OTA production was determined by HPLC (n = 4). Antimicrobial treatment with 0.9% EO was more effective on fungal growth when the inoculation took place on slices than in wounded skin (p

Fungi are common spoilers of intermediate moisture foods such as bakery products. Brioche are bakery products prone to fungal spoilage due to their pH (5.8-6.2) and water activity (aw) (0.82-0.84). The aims of the present study were: (i) the identification of fungal species occurring in brioche products, (ii) the in vitro assessment of their growth potential, and (iii) the development of a validated growth model following the gamma concept. A total of 102 fungal strains were isolated, with Penicillium sp., Cladosporium sp., and Aspergillus sp. being the main genera, representing 90% of the isolates. Given the isolation frequency, any potential fungal prevalence throughout the bakery processs and/or the results of in vitro assessment of fungal growth potential under conditions mimicking brioche (pH, aw, temperature), Aspergillus flavus, Aspergillus fumigatus, and Penicillium sp. were selected for the development of the gamma model. According to in vitro validation, the model successfully predicted fungal growth, while on in situ experiments, the intrinsic parameters (aw and/or level of used preservative) of brioche in combination with packaging conditions (modified atmosphere) did not allow fungal growth.

Listeria monocytogenes enters the food processing facility via environment, or contaminated raw materials. To increase the understanding of L. monocytogenes environmental contamination in the meat and dairy food sector, six European scientific institutions sampled twelve food processing environments (FPEs) in a harmonized methodological approach. The selection of six previously assumed uncontaminated (UC) FPEs and six contaminated (C) FPEs was based on the L. monocytogenes occurrence information originating from the time prior to the current study. An aim of the study was to highlight, that FPEs regarded for years as uncontaminated, may also become L. monocytogenes contaminated and repeated environmental sampling could help to identify the potential sources of contamination. From a total of 2242 FPE samples, L. monocytogenes was present in 32% and 8.8% of meat and dairy processing environments, respectively. In the actual study, each FPE was contaminated with L. monocytogenes on at least one sampling occasion. Three contamination scenarios could be observed: (i) sporadic contamination in the interface of raw material reception and hygienic areas, (ii) hotspot contamination in the hygienic processing areas (iii), and widely disseminated contamination in the entirely FPE. These data demonstrate that L. monocytogenes are common colonizers of FPEs in the European processing facilities sampled and that a consistent cross-contamination risk exists. To avoid food contamination, a risk assessment approach should assign risk levels to critical control areas (CCAs) and identify those where cross-contamination should be essentially excluded.

Despite the increasing pomegranate consumption, the ready-to-eat (RTE) arils are highly perishable and this negatively impacts their commercialization. Nowadays, mild pre-packaging decontamination interventions (washing with sanitizing agents or exposure to ultraviolet light) in sequence or not with modified atmospheres packaging technologies are applied. Even though, the latter combination of methods provides them a shelf-life of 10–14 days at cold storage, several negative effects have been also reported (i.e., degradation of anthocyanins). Thus, the aim of the study was to evaluate the effect of alternative, mild antimicrobials such as the vapors of distillery ethanol and brandy on microbial, physical, textural, sensorial, and multispectral imaging attributes of RTE arils during storage at different temperatures in perforated bags. Lactic acid bacteria (LAB) and yeasts/moulds were the dominant spoilage microbiota of RTE arils, regardless of storage temperature and antimicrobial. Vapors produced by both volatile antimicrobials significantly inhibited (p − 1 (day 23), the respective counts on arils treated with distillery ethanol or brandy followed the order: 4.9 log CFU g − 1 (1 mL of ethanol) > 3.9 log CFU g − 1 (1 mL of brandy) > 2.2 log CFU g − 1 (2 mL of ethanol) > 1.2 log CFU g − 1 (2 mL of brandy). Moreover, arils exposed to distillery ethanol and brandy vapors showed lower weight loss (%) compared to controls, while the firmness was reduced, regardless of treatment and storage temperature. Color measurements and evaluation of multiple sensory attributes revealed that arils exposed to brandy vapors showed more intense red color and look fresher compared to controls for longer storage time. The latter observation was also validated by multispectral image analysis, since the results suggested that arils packaged with distillery ethanol or brandy maintained their anthocyanin and carotenoids content at higher levels than controls, at 4 °C. Thus, such preservation methods may open new perspectives on mild antimicrobial packaging in order to extend shelf-life of perishable minimally processed fruits, like pomegranate RTE arils.

The objective of this study was to correlate the relative transcription of Listeria monocytogenes (strains C5, 6179) stress- (gad2, sigB) and virulence- (prfA) associated genes following habituation at twenty-five pH (4.8, 5.0, 5.2, 5.5, 6.4) and NaCl (2, 4, 6, 8, 10% w/v) combinations at 7 °C, with the survival against subsequent exposure to severe acid stress (pH 2.0 at 37 °C). Our findings pointed out the inter-strain variation governing growth inhibiting conditions (pH ≤5.0 and NaCl ≥6%), where C5 was less affected (a reduction of 2.0-3.0 log CFU/mL) than 6179 which was reduced by 4.0-6.0 log CFU/mL at the end of storage. Nevertheless, the higher the habituation at the growth permitting (pH ≥5.5; NaCl ≤4% w/v) or growth inhibiting conditions, the higher the acquired acid resistance or sensitization, respectively. At day 2, gad2 increased relative transcriptional levels are more related to elevated acid resistance, while at day 6 both gad2 transcriptional levels and upregulation of sigB were correlated to low log reductions and high DpH:2.0-values against severe acid stress. Regarding virulence, the increased transcriptional levels of prfA at day 2 were correlated to adverse pH and NaCl combinations, while prolonged stay in suboptimal conditions as well as exposure to severe acid stress resulted in general activation of the virulence regulator. Such data could definitely contribute in designing safe intervention strategies and additionally integrate -omics aspects in quantitative microbial risk assessment. (Less)

Objectives The potential positive health effects of carob-containing snacks are largely unknown. Therefore, the aims of these studies were to determine the glycemic index (GI) of a carob snack compared with chocolate cookie containing equal amounts of available carbohydrates and to compare the effects of a carob versus chocolate cookie preload consumed as snack before a meal on (a) short-term satiety response measured by subsequent ad libitum meal intake, (b) subjective satiety as assessed by visual analog scales and (c) postprandial glycemic response. Methods Ten healthy, normal-weight volunteers participated in GI investigation. Then, 50 healthy, normal-weight individuals consumed, crossover, in random order, the preloads as snack, with 1-wk washout period. Ad libitum meal (lunch and dessert) was offered. Capillary blood glucose samples were collected at baseline, 2 h after breakfast, just before preload consumption, 2 h after preload, 3 h after preload, just before meal (lunch and dessert), 1 h after meal, and 2 h after meal consumption. Results The carob snack was a low GI food, whereas the chocolate cookie was a high GI food (40 versus 78, respectively, on glucose scale). Consumption of the carob preload decreased the glycemic response to a following meal and to the individual's feelings of hunger, desire to eat, preoccupation with food, and thirst between snack and meal, as assessed with the use of visual analog scales. Subsequently, participants consumed less amounts of food (g) and had lower total energy intake at mealtimes. Conclusions The carob snack led to increased satiety, lower energy intake at meal, and decreased postmeal glycemic response possibly due to its low GI value. Identifying foods that promote satiety and decrease glycemic response without increasing the overall energy intake may offer advantages to body weight and glycemic control.

The present study aimed to evaluate the effect of AB vapors on microbial, physicochemical, and sensory profile of pork meat stored in different MAP conditions. Pork pieces (10g) and cotton/cellulose absorbent cloths (2×2cm) were placed into compartmentalized Petri-dishes in two sections. Aliquots (1mL) of water (control), 30% v/v and 40% v/v ethanol, whisky, brandy, tsipouro, raki, and ouzo were added separately to the cotton/cellulose absorbent cloths. Each pork sample was placed in one compartment and cotton/cellulose absorbent cloths supplemented with different ABs were placed in a separate compartment of each Petri-dish. Samples were packaged in 40% CO2: 30% O2: 30% N2 and 80% O2: 20% CO2 and stored at 4 and 10°C. Total viable counts, Pseudomonas sp., Brochothrix thermosphacta, lactic acid bacteria, yeasts and molds, and Enterobacteriaceae, were enumerated during storage. Changes in pH, color (L*, a*, b*), odor, taste, and overall appearance of pork meat were also evaluated along with changes in organic acid levels via HPLC. At 4°C, lactic acid bacteria and B. thermosphacta were the dominant organisms under 40% CO2: 30% N2: 30% O2 and 80% O2: 20% CO2, respectively, while at 10°C, lactic acid bacteria dominated in both MAP conditions. All applied ABs were effective (p

Analysis for Listeria monocytogenes by ISO11290-1 is time-consuming, entailing two enrichment steps and subsequent plating on agar plates, taking five days without isolate confirmation. The aim of this study was to determine if a polymerase chain reaction (PCR) assay could be used for analysis of the first and second enrichment broths, saving four or two days, respectively. In a comprehensive approach involving six European laboratories, PCR and traditional plating of both enrichment broths from the ISO11290-1 method were compared for the detection of L. monocytogenes in 872 food, raw material and processing environment samples from 13 different dairy and meat food chains. After the first and second enrichments, total DNA was extracted from the enriched cultures and analysed for the presence of L. monocytogenes DNA by PCR. DNA extraction by chaotropic solid-phase extraction (spin column-based silica) combined with real-time PCR (RTi-PCR) was required as it was shown that crude DNA extraction applying sonication lysis and boiling followed by traditional gel-based PCR resulted in fewer positive results than plating. The RTi-PCR results were compared to plating, as defined by the ISO11290-1 method. For first and second enrichments, 90% of the samples gave the same results by RTi-PCR and plating, whatever the RTi-PCR method used. For the samples that gave different results, plating was significantly more accurate for detection of positive samples than RTi-PCR from the first enrichment, but RTi-PCR detected a greater number of positive samples than plating from the second enrichment, regardless of the RTi-PCR method used. RTi-PCR was more accurate for non-food contact surface and food contact surface samples than for food and raw material samples especially from the first enrichment, probably because of sample matrix interference. Even though RTi-PCR analysis of the first enrichment showed less positive results than plating, in outbreak scenarios where a rapid result is required, RTi-PCR could be an efficient way to get a preliminary result to be then confirmed by plating. Using DNA extraction from the second enrichment broth followed by RTi-PCR was reliable and a confirmed result could be obtained in three days, as against seven days by ISO11290-1.

The objective of this study was to develop a model system for the prediction of the impact of temperature and in-package % CO2 on the microbial spoilage of fresh‒cut vegetables with high respiration rate independent of packaging characteristics and post-harvest physiology. Model development was based on study of rocket pulp stored under 0–20% O2: 20-0% CO2: 80% N2 at 0–15 °C. Growth of pseudomonads and lactic acid bacteria (LAB) was primary modelled by Baranyi model, while growth rate was further modeled as a function of storage temperature and % CO2 by a polynomial model. Both growth models were validated against various fresh‒cut vegetables of high respiration rate, modified atmosphere packaging, and packaging films, under isothermal and dynamic temperature conditions. Variations of gas concentration of rocket pulp was eliminated or significantly decreased (p

Different physicochemical and microbiological characteristics of cheeses may affect Listeria monocytogenes potential to grow, survive, or exhibit an acid adaptive response during storage and digestion. The objectives of the present study were to assess: i) the survival or growth potential of L.monocytogenes on various cheeses during storage, ii) the effect of initial indigenous microbiota on pathogen growth in comparison to expected growth curves retrieved by existing predictive models, and iii) the impact of habituation on/in cheeses surfaces on the subsequent acid resistance during simulated gastric digestion. Portions of cream (Cottage and Mascarpone), soft (Anthotyros, Camembert, Mastelo®, Manouri, Mozzarella, Ricotta), and semi-hard (Edam, Halloumi, Gouda) cheeses were inoculated with ca. 100CFU/g or cm2 of L.monocytogenes and stored under vacuum or aerobic conditions at 7°C (n=4). The impact of varying (initial) levels of starter culture or indigenous spoilage microbiota on pathogen growth was evaluated by purchasing cheese packages on different dates in relation to production and expiration date (subsequently reflecting to different batches) mimicking a potential situation of cheese contamination with L.monocytogenes during retail display. Values of pH and aw were also monitored and used to simulate growth of L. monocytogenes by existing models and compare it with the observed data of the study. Survival in simulated gastric fluid (SGF) (pH1.5; HCl; max. 120min) was assessed at three time points during storage. Mascarpone, Ricotta, Mozzarella, Camembert, and Halloumi supported L.monocytogenes growth by 0.5-0.8logCFU/g or cm2per day, since low initial levels of total viable counts (TVC) (1.8-3.8logCFU/g or cm2) and high pH/aw values (ca. 6.23-6.64/0.965-0.993) were recorded. On Cottage, Anthotyros, Manouri, Mastelo®, Edam, and Gouda, the pathogen survived at populations similar or lower than the inoculation level due to the high reported competition and/or low pH/aw during storage. L. monocytogenes growth was significantly suppressed (p

Five composites of yeast and six of bacterial isolates from fermented products were studied, in order to assess their ability to inhibit Aspergillus carbonarius growth and reduce OTA concentration in culture media and beverages. The antagonistic effect of the above composites against A. carbonarius growth was studied in synthetic grape medium of pH 3.5 and a w 0.98, 0.95, 0.92 after incubation at 25 °C. Different combinations of initial inocula of bacteria or yeast composites and fungi were used (10 2 cfu/mL vs 10 5 spores/mL; 10 5 cfu/mL vs 10 2 spores/mL; and 10 5 cfu/mL vs 10 5 spores/mL). Regarding the OTA reduction experiment, 10 3 and 10 7 cfu/mL of the bacteria and yeast composites were inoculated in liquid media of different pH (3.0, 4.0, 5.0, and 6.1 or 6.5) and initial OTA concentration (50 and 100 μg/L) and incubated at 30 °C. Moreover, grape juice, red wine, and beer were supplemented with 100 μg/L of OTA and inoculated with composites of 16 yeasts (16YM) and 29 bacterial (29BM) strains (10 7 cfu/mL) to estimate the kinetics of OTA reduction at 25 °C for 5 days. Fungal inhibition and OTA reduction were calculated in comparison to control samples. None of the bacterial composites inhibited A. carbonarius growth. The high inoculum of yeast composites (10 5 cfu/mL) showed more efficient fungal inhibition compared to cell density of 10 2 cfu/mL. All yeast composites showed higher OTA reduction (up to 65%) compared to bacteria (2–25%), at all studied assays. The maximum OTA reduction was obtained at pH 3.0 by almost all yeast composites. For all studied beverages the decrease in OTA concentration was higher by yeasts (16YM) compared to bacteria (29BM). The highest OTA reduction was observed in grape juice ( ca 32%) followed by wine ( ca 22%), and beer ( ca 12%). The present findings may assist in the control of A. carbonarius growth and OTA production in fermented foodstuffs by the use of proper strains of technological importance.

The objectives of this study were: (a) to evaluate the potential of the ELISA method in the determination of the produced OTA by Aspergillus ochraceus and Aspergillus carbonarius in malt extract agar (MEA) at different pH (3.9, 5.1, 5.9, 6.8), water activity (aw) (0.87, 0.93, 0.99), and temperature (10, 15, 20, 25, 30, 40 °C) levels, providing a rapid screening for the optimum and marginal conditions of OTA production, (b) to comparatively evaluate the performance of ELISA and HPLC method, and (c) to evaluate the ability of A. ochraceus to produce OTA in rehydrated Corinth raisins during storage for 36 days. Two independent experiments were carried out to estimate OTA production on MEA and Corinth raisins. The produced OTA was evaluated qualitatively by the ELISA method and selected cases were verified by HPLC. The levels of OTA decreased with water activity, whereas pH seemed to have no specific effect. Furthermore, A. ochraceus produced maximum amounts of OTA on raisins at the 24th day of incubation, indicating that the endogenous microflora may restrictively affect OTA production. The knowledge of optimal and marginal levels of ecological factors in order to optimise post-harvest and storage of food products may significantly affect the production of OTA. Moreover, endogenous microflora of certain foodstuffs may cause OTA detoxification and consequently reduction of OTA levels; a fact that has to be taken into account in food commodities such as raisins, grapes, and wine.

The aim of the present work was to evaluate the efficacy of Na-alginate edible films as vehicles for delivering probiotic bacteria to sliced ham with or without pretreatment using high pressure processing (HPP). Three strains of probiotic bacteria were incorporated in Na-alginate forming solution. Ham slices (with or without pretreatment using HPP at 500 MPa for 2 min) were packed under vacuum in contact with the films and then stored at 4, 8 and 12 °C for 66, 47 and 40 days, respectively. Microbiological analysis was performed in parallel with pH and color measurements. Sensory characteristics were assessed, while the presence and the relative abundance of each probiotic strain during storage was evaluated using pulsed field gel electrophoresis. In ham slices without HPP treatment, probiotic bacteria were enumerated above 10⁶ CFU/g during storage at all temperatures. Same results were obtained in cases of HPP treated samples, but pH measurements showed differences with the latter ones exhibiting higher values. Sensory evaluation revealed that probiotic samples had a more acidic taste and odor than the control ones, however these characteristics were markedly compromised in samples treated with HPP. Overall, the results of the study are promising since probiotic bacteria were successfully delivered in the products by edible films regardless of the HPP treatment.

The ubiquitous nature of microbes renders their presence inevitable in the food-processing chain as well as in domestic kitchens. Their introduction into a sterile or well-disinfected environment and their establishment on an abiotic or biotic surface is termed contamination. The major contamination source in such environments derives from the incoming raw materials, which may be carriers of a large and diverse association of spoilage bacteria, such as pseudomonads, enterobacteria, lactic acid bacteria, enterococci, yeasts, and molds. From a food safety aspect, these raw materials may also serve as vehicles of pathogenic microorganisms, including Listeria monocytogenes, Salmonella spp., Escherichia coli, Vibrio parahaemolyticus, Shigella, and Campylobacter. These microorganisms may be part of the indigenous microora of the food (of plant or animal origin), retrieved from the direct contact with the growth environment or introduced to the food during harvest and subsequent handling in the eld and/or during slaughter and further-processing and storage. Similarly, the working staff in a food-processing environment or the cook in a domestic kitchen may also assist in the introduction and spreading of undesirable6.1 Routes and Vehicles of Bacterial Immigration in the Food Industry and the Domestic Environment 89 6.1.1 Food Handlers 91 6.1.2 Cleaning Sponges, Cloths, and Towels 92 6.1.3 Kitchen Utensils and Storage Containers 92 6.1.4 Other Vehicles of Cross-Contamination 936.2 Factors Affecting Attachment of Pathogens on Food Contact Surfaces-Biolm Formation ..... 93 6.2.1 Type of Surface 94 6.2.2 Microbial Strain 95 6.2.3 Temperature 96 6.2.4 Surface Conditioning 97 6.2.5 Mixed-Species Biolm Formation 97 6.2.6 Persistence, Survival, and Stress Hardening of Attached Populations 976.3 Stochastic Description of Bacterial Transfer 99 6.3.1 Transfer between Abiotic Surfaces and Foods of Plant Origin 100 6.3.2 Transfer between Abiotic Surfaces and Foods of Animal Origin 101 6.3.3 Modeling Bacterial Transfer 1036.4 Concluding Remarks 105 References 105microbes, especially of pathogenic nature. In particular, food handlers may be potential disease vectors without experiencing any obvious symptoms. For instance, Staphylococcus aureus is commonly encountered on human skin and skin wounds, nose, or throat, and it can be easily transferred to foods or food-related surfaces. Other sources of undesirable contamination in the food industry or a kitchen environment include the water used for washing of the equipment, utensils, or the pets and pests that have access to a food preparation site, which may excrete a variety of food-poisoning microorganisms. For these reasons, it is of high importance that the hygienic level of the incoming raw materials as well as that of the food handlers should be strictly maintained and regularly validated, while all the food-related environments should also be protected from animals and pests.

Packaging as the fi nal stage of food production chain consists one of the main factors for ensuring quality and safety of the fi nal product. Given that foods are dynamic systems, the improvement of classic packaging techniques (e.g., modifi ed atmospheres) or developing of new ones is a continuous challenge for the food industry. In the last decade, among the most challenging packaging techniques for research, was active packaging. Specifi cally, active packaging is a system that involves interactions between food and packaging atmosphere, packaging material, or certain (bio-) active package components, in order to maintain or increase the nutritional, quality, and safety attributes of packaged food (Coma 2008). Oxygen scavengers, carbon dioxide emitters/absorbers, moisture and ethylene absorbers, fl avor releasing/absorbing systems, and antimicrobial agents are among the most distinctive types of active packaging. Antimicrobial agents may either be released through evaporation in the headspace (i.e., essential oils) or migrate into the food through diffusion and partitioning (i.e., nisin, organic acids). Migration could take place by adding directly the antimicrobial compound onto the surface of the food product or by incorporating it into edible carrier materials such as fi lms or coatings (Fig. 1).

The present study aimed: (i) to develop models for the combined effect of water activity (0.99, 0.94 and 0.90), microstructure expressed as 0, 5, 10 and 20% w/v gelatin, and temperature (15, 20 and 25 °C), on growth and OTA production rates by Aspergillus carbonarius; and (ii) to evaluate the performance of the developed models on food matrices (jelly, custard and marmalade) of different viscosity at pH 5.5. The square root of biomass increase rate (fungal growth rate) and OTA production rate were determined by the Baranyi model and were further modeled as a function of temperature, gelatin concentration and aw by applying polynomial models. Time for visible growth and the upper asymptote of the OTA production curve were also determined by the Baranyi model. Increase in gelatin concentration resulted in a significant delay in all parameters describing fungal growth and OTA production rates, at all temperatures and aw. The effect of microstructure on fungal growth and OTA production rates was less evident at stress conditions of aw and temperature. Detection time for visible fungal growth was markedly influenced by aw and temperature. Coefficients of determination were 0.899 and 0.887 for the models predicting the square root ( μ max ) of growth and OTA production rate, respectively. Predictions of growth rate agreed well with the recorded data of custard and marmalade, while observations of OTA production rate indicated low agreement with model predictions, in all food matrices except for marmalade. The present findings may provide a basis for reliable assessment of the risk of fungal growth and OTA production in foods of different structural and rheological properties.