Total Aerobic Mesophilic Counts Research Articles

Synthesis and Characterization of Janus fenugreek Seed Gum-based Film for Food Packaging and Wound Dressing Applications

The use of plant-derived natural gum polysaccharides in food packaging and biomedicine is growing due to their biocompatibility, biodegradability, film-forming ability, abundant functional groups, and potential for chemical or physical modification to develop novel materials. In this study, fenugreek (Trigonella foenum-graecum) seed gum (FSG)-based Janus films with glycerol (GLY) as a plasticizer in varying concentrations (2%, 5%, 7%, and 10% w/w) were synthesized for potential food packaging and biomedical applications. The glycerol concentration significantly affected the stability, microstructure, moisture content, and solubility of the film, with 5% GLY yielding the most stable films. The water solubility was gradually increased with increasing the GLY content in the film sample. The film exhibited strong radical scavenging activity against DPPH assays, with an IC50 value of 158.73±0.013 µg/mL. The total phenolic content (TPC) and total flavonoid content (TFC) of the film were found to be 88.21±0.012 mg/g in gallic acid equivalents (GAE) and 9.36±0.018 mg/g in quercetin equivalents (QE), respectively. The pristine FSG film exhibited antibacterial activity against Staphylococcus aureus, Escherichia coli, and the fungal strain Candida albicans, which was significantly enhanced by incorporating the antibacterial drug penicillin. Additionally, we examined the impact of different films on chicken meat and cheese by monitoring changes in weight loss, color, pH, total aerobic mesophilic counts (TAMC), and psychrotrophic bacterial counts (PBC) during storage. Our results demonstrated that the samples packaged with pristine FSG film exhibited significantly lower TAMC and PBC values and slowed down the increase in pH values compared to the control samples, which further decreased by incorporating antimicrobial drug. These findings indicated that the Janus pristine FSG film is suitable for food packaging. Further, antimicrobial drugs incorporated into FSG film could be potential candidates for wound dressing applications.

In-package cold atmospheric plasma processing for shelf-life extension of gilthead seabream (Sparus aurata) fillets.

In-package cold atmospheric plasma (CAP) processing, which refers to the generation of CAP inside a sealed package, enables a local disinfecting reaction, allowing no post-process contamination and extending the shelf-life (SL) of perishable food products, such as fresh fish. In the present study, four in-package CAP treatments, differing in frequency and processing time, were applied on fresh gilthead seabream (Sparus aurata) fillets, prepacked in low-permeability pouches. Fish SL was evaluated during isothermal storage at 2°C, whereas untreated packaged fillets were used as control samples. The SL assessment of the fish fillets was based on microbial enumeration of total aerobic mesophilic count (TMC), total aerobic psychrotrophic count (TPC), Pseudomonas spp., Enterobacteriaceae, and lactic acid bacteria (LAB), pH measurement, determination of color and texture parameters, lipid oxidation, total volatile basic nitrogen (TVB-N) measurement, and sensory evaluation. All CAP treatments were effective against microbial inhibition in fish fillets, especially regarding TMC, TPC, and Pseudomonas spp., resulting in maximum reduction of 1.49, 1.24, and 1.43logCFU/g, respectively, compared to the control samples after 16 days of storage. However, minor effect was observed against Enterobacteriaceae and no effect against LAB. CAP processing did not affect the color and texture parameters of fish fillets, and TVB-N production was slightly reduced in CAP-treated samples; however, lipid oxidation was accelerated, especially at the more intense processing conditions, by a maximum of 75.5%. The results of the study indicated that in-package CAP processing could be effectively applied for inhibiting spoilage during refrigerated storage and extending SL of fresh fish fillets. PRACTICAL APPLICATION: In-package cold atmospheric plasma (CAP) processing was tested on gilthead seabream fillets, a highly perishable product with high commercial potential if its shelf-life can be extended through minimal processing. The food industry could benefit from in-package CAP technology as it is a cost effective nonthermal processing method while preventing post-processing contamination of the products. Although in-package CAP processing has not been extensively tested on fish, this study examined the quality and shelf-life of a highly perishable fish species, and the results could be further used as a reference for processing optimization of the CAP treatments.

Effect of thyme, ginger, and their nano-particles on growth performance, carcass characteristics, meat quality and intestinal bacteriology of broiler chickens

This study was conducted to evaluate the effects of thyme, ginger, and their nano-particles, as alternatives to antibiotic growth promotors (AGP), on productive performance, carcass traits, meat quality and gut health of broiler chickens. A total of 270 one-day-old broiler chicks were randomly distributed into 6 groups, each consisting of 3 replicates (n = 15 chicks/replicate). The birds in group 1 were fed the control diet which contained neither antibiotic growth promotors nor phytogenic feed additives (PFA). Birds in group 2 were fed diets containing 0.05% of AGP (Bacitracin methylene disalicylate). Chicks in group 3 and 4 were fed diets supplemented with 1.0% of thyme and ginger, respectively, whereas birds in group 5 and 6 were offered diets including 0.10% of nano-thyme and nano-ginger, respectively. The experiment lasted for 35 days. It was found that thyme and ginger with their nano-products, like the antibiotic, improved the body weight, weight gain and feed conversion rate of birds. The effect of ginger and nano-ginger on body weight and weight gain was greater than other treatments. During the overall feeding period, the feed cost of production was the highest in antibiotic group, but was the lowest in ginger and nano-ginger treatments. There was no effect of dietary treatments on carcass yield or organs weight except bursa of Fabricius and abdominal fat. Thyme, ginger and their nano-composites increased the weight of bursa and reduced the abdominal fat amount. The phytogenic additives and their nano-particles improved the colour, water holding capacity, and flavor of meat. Moreover, these additives reduced the total intestinal bacterial count as well as the total aerobic mesophilic count of meat. The effect of PFA and their nano-particles on the bacterial count was similar to that of antibiotic. In conclusion, thyme and ginger with their nano- particles can be considered as promising agents in feeding of broilers to improve the growth performance, gut health and meat quality. Moreover, these additives can be used as alternatives to AGP to overcome its health hazards and the high cost. The nanotechnology of herbal plants enables them to be added in smaller amounts in poultry diets with producing the same effect of raw ingredients, and this could be due to the higher bioavailability.

Hunted Wild Boars in Sardinia: Prevalence, Antimicrobial Resistance and Genomic Analysis of Salmonella and Yersinia enterocolitica.

The objective of this investigation was to evaluate Salmonella and Yersinia enterocolitica prevalence in wild boars hunted in Sardinia and further characterize the isolates and analyse antimicrobial resistance (AMR) patterns. In order to assess slaughtering hygiene, an evaluation of carcasses microbial contamination was also carried out. Between 2020 and 2022, samples were collected from 66 wild boars hunted during two hunting seasons from the area of two provinces in northern and central Sardinia (Italy). Samples collected included colon content samples, mesenteric lymph nodes samples and carcass surface samples. Salmonella and Y. enterocolitica detection was conducted on each sample; also, on carcass surface samples, total aerobic mesophilic count and Enterobacteriaceae count were evaluated. On Salmonella and Y. enterocolitica isolates, antimicrobial susceptibility was tested and whole genome sequencing was applied. Salmonella was identified in the colon content samples of 3/66 (4.5%) wild boars; isolates were S. enterica subs. salamae, S. ser. elomrane and S. enterica subs. enterica. Y. enterocolitica was detected from 20/66 (30.3%) wild boars: in 18/66 (27.3%) colon contents, in 3/66 (4.5%) mesenteric lymph nodes and in 3/49 (6.1%) carcass surface samples. In all, 24 Y. enterocolitica isolates were analysed and 20 different sequence types were detected, with the most common being ST860. Regarding AMR, no resistance was detected in Salmonella isolates, while expected resistance towards β-lactams (blaA gene) and streptogramin (vatF gene) was observed in Y. enterocolitica isolates (91.7% and 4.2%, respectively). The low presence of AMR is probably due to the low anthropic impact in the wild areas. Regarding the surface contamination of carcasses, values (mean ± standard deviation log10 CFU/cm2) were 2.46 ± 0.97 for ACC and 1.07 ± 1.18 for Enterobacteriaceae. The results of our study confirm that wild boars can serve as reservoirs and spreaders of Salmonella and Y. enterocolitica; the finding of Y. enterocolitica presence on carcass surface highlights how meat may become superficially contaminated, especially considering that contamination is linked to the conditions related to the hunting, handling and processing of game animals.

Levels and types of microbial contaminants in different plant-based ingredients used in dairy alternatives

In this study levels and types of microbial contaminants were investigated in 88 different plant-based ingredients including many that are used to manufacture dairy alternatives. Studied ingredients encompassed samples of pulses (pea, faba bean, chickpea, and mung bean), cereals/pseudocereals (oat, rice, amaranth and quinoa) and drupes (coconut, almond and cashew). The microbial analysis included: i) total viable count (TVC), ii) total aerobic mesophilic spore count (TMS), iii) heat resistant aerobic thermophilic spore count (HRTS), iv) anaerobic sulfite reducing Clostridium spore count (SRCS), and v) Bacillus cereus spore count (BCES). Microorganisms isolated from the counting plates with the highest sample dilutions were identified using 16S rRNA and MALDI-TOF MS analyses.Many of the investigated ingredients showed a high proportion of spores as part of their total aerobic mesophilic counts. In 63 % of the samples, the difference between TVC and TMS counts was 1 Log10 unit or less. This was particularly the case for the majority of pea isolates and concentrates, faba bean isolates, oat kernels and flakes, and for single samples of chickpea isolate, almond, amaranth, rice, quinoa, and coconut flours. Concentrations of TVC ranged between <1.0 and 5.3 Log10 CFU/g in different samples, and TMS varied between <1.0 and 4.1 Log10 CFU/g. Levels of HTRS, BCES and SRCS were generally low, typically around or below the LOD of 1.0 Log10 CFU/g.In total, 845 individual bacterial colonies were isolated belonging to 33 different genera. Bacillus licheniformis and B. cereus group strains were most frequently detected among Bacillus isolates, and these species originated primarily from pea and oat samples. Geobacillus stearothermophilus was the main species encountered as part of the HRTS. Among the Clostridium isolates, Clostridum sporogenes/tepidum were predominant species, which were mostly found in pea and almond samples. Strains with potential to cause foodborne infection or intoxication were typed using the PCR-based method for toxin genes detection. In the B. cereus group, 9 % of isolates contained the ces gene, 28 % contained hbl, 42 % cytK, and 69 % were positive for the nhe gene. Absence of the boNT-A and -B genes was confirmed for all isolated C. sporogenes/tepidum strains. Nearly all (98 %) B. licheniformis isolates were positive for the lchAA gene.Insight into the occurrence of microbial contaminants in plant-based ingredients, combined with knowledge of their key inactivation and growth characteristics, can be used for the microbial risk assessment and effective design of plant-based food processing conditions and formulations to ensure food safety and prevent spoilage.

Effect of rearing system (free-range vs cage) on gut and muscle histomorphology and microbial loads of Italian White breed rabbits.

The growing consumers' interest on animal welfare has raised the request of products obtained by alternative rearing systems. The present study was conducted to assess the influence of housing system on gut and muscle morphology and on microbial load in rabbits reared under free-range (FR) and cage system (CS). A total of forty weaned (35 days of age) male Italian White breed rabbits were allotted according to the rearing system, and at 91 days of age were randomly selected and slaughtered for the morphological evaluation of tissue from duodenum and longissimus lumborum. Morphometric analysis of the villus height, villus width, crypt depth, villus height/crypt depth ratio, and villus surface was performed. The microbial loads on hind muscle was determined by total mesophilic aerobic count (TMAC), Escherichia coli and Enterobacteriaceae; whereas, total anaerobic bacteria count (TABC) and TMAC, E. coli and Enterobacteriaceae was determined on caecal content. Rearing system did not interfere with the duodenum and muscle histomorphology in both rabbit groups. Similarly, microbial load of caecal content showed no significant differences on the TABC and TMAC. Conversely, significant difference was found for E. coli strains in caecal content, with the lower counts in FR compared to CS rabbits (p<0.01). Microbiological assay of muscle revealed significant lower TMAC in FR vs CS rabbits (p< 0.05). All rabbit meat samples were negative for E. Coli and Enterobacteriaceae. Free-range could be considered a possible alternative and sustainable rearing system in rabbits to preserve gut environment and muscle quality.

Evaluation of vacuum packaging for extending the shelf life of Sardinian fermented sausage

Salsiccia sarda or Sardinian fermented sausage is a traditional dry-fermented sausage included in the list of traditional food products of Sardinia (Italy). At the request of some producing plants, the possibility of extending the shelf life of the vacuum-packed product up to 120 days was evaluated. Manufacturing of 90 samples, representing 3 different batches of Sardinian fermented sausage was carried out in two producing plants (A and B). In the packaged product and subsequently every 30 days for four months (T0, T30, T60, T120), the following analyses were conducted on all samples: physicochemical characteristics, total aerobic mesophilic count, Enterobacteriaceae count, detection of Listeria monocytogenes, Salmonella spp., mesophilic lactic acid bacteria, and coagulase-positive Staphylococci. Moreover, surfaces in contact and surfaces not in contact with food were sampled in both producing plants. Sensory profile analysis was also performed for every analysis time. At the end of the extended shelf life, pH values were equal to 5.90±0.11 (producing plant A) and 5.61±0.29 (producing plant B). Water activity mean values at T120 were 0.894±0.02 (producing plant A) and 0.875±0.01 (producing plant B). L. monocytogenes was detected in 73.3% (33/45) of the samples from producing plant A, with mean levels of 1.12±0.76 log10 CFU/g. In producing plant B, L. monocytogenes was never detected. Enterobacteriaceae were detected in 91.1% (41/45) of samples in producing plant A with mean values of 3.15±1.21 log10 CFU/g, and in 35.5% (16/45) samples in producing plant B samples with mean values of 0.72±0.86 log10 CFU/g. Salmonella and Staphylococcus aureus were never detected. Regarding environmental samples, the sites that were most contaminated by L. monocytogenes were the bagging table (contact surface) and processing room floor drains (non-contact surface) with a prevalence of 50% each (8/16 positive samples for both sampling sites). Sensory analysis results showed that at T30 the overall sensory quality was at its highest; moreover, the visual-tactile aspect, the olfactory characteristics, the gustatory aspects, and the texture showed significant differences in samples throughout the shelf life, with a decreased intensity at 120 days of storage. Overall, the quality and sensory acceptance of the vacuum-packed Sardinian fermented sausage were not affected until 120 days of shelf-life. However, the possible contamination by L. monocytogenes calls attention to the hygienic management of the entire technological process. The environmental sampling was confirmed as a useful verification tool during control.

Effect of Two-Step Sous Vide Cooking and Storage on Microbiological and Oxidative Stability of Chicken Breast

A two-step sous vide method, which included a low temperature initial stage, was shown to improve texture parameters, increase the solubility of proteins, and decrease the cook loss in chicken breasts. The current work was designed to determine the effect of two-step sous vide and subsequent storage on the microbiological and oxidative stability of chicken breasts. Inoculated chicken breasts were vacuum packaged and cooked at two temperatures, 50 °C and 60 °C, combined in different ratios of the same total cooking time (120 min), and then stored for 21 days at 4 °C, 10 °C, and -20 °C, and compared with the one-step temperature treatment (60 °C for 120 min). One-step sous vide treatment resulted in the total inactivation of Enterococcus faecalis NCAIM B. 01312. Meanwhile, the two-step sous vide treatments resulted in a higher than 3 log reduction in Enterococcus faecalis NCAIM B. 01312, reaching the target pasteurization performance criterion of sous vide for poultry meat. Lipid oxidation and the odor of all chicken breasts remained acceptable for 21 days of storage at 4 °C and -20 °C. Conversely, all chicken breasts had higher lipid oxidation rates and odor after 21 days of storage at 10 °C. Two-step-sous-vide-treated chicken breasts were found to be microbiologically stable regarding Enterococcus faecalis NCAIM B. 01312 and total mesophilic aerobic counts during 21 days of storage at 4 °C and -20 °C, in contrast with those stored at 10 °C. It can be concluded that two-step-sous-vide-cooked chicken breasts had acceptable oxidative and microbiological stability during chilled and frozen storage, similar to one-step sous vide ones. These outcomes highlight that two-step heat treatment can be used as an alternative cooking method to improve the quality properties without compromising the storage life of chicken breasts.

Comparison of meat quality characteristics of dry aged lamb loins and optimization of dry aging process.

The purpose of the present study was to investigate the physicochemical characteristics, meat quality, oxidative stability and sensory properties of lamb meat during 0, 7 and 14 day of the dry aging process. The M. longissimus lumborum (LL) and M. longissimus thoracis (LT) muscles from male Akkaraman lambs were used. The pH values of the LT and LL cuts were not changed during the aging periods. The LT cuts had significantly higher weight loss, a* and b* values, and lower shear force compared to the LL cuts. However, dry aging led to greater decreases in shear force in the LL cuts on 7th day of aging. The total mesophilic aerobic counts, total psychrophilic counts, Enterobacteriaceae counts, lactic acid bacteria, and yeast-mold counts were increased during the aging process. The sensory panel scoring showed a significant difference in the LL cuts and no significant difference in the LT cuts compared to the control group. There were significant changes in sensory panel scores for the LL cuts, whereas there were no significant changes for the LT cuts according to the non-aged samples. In conclusion, dry aging improved the quality of both cuts, however, the LL muscle of lamb was more suitable for dry aging. Moreover, 7 days were sufficient to produce the desired sensory properties in the lamb loins. Increasing the aging time from 7 to 14 days did not appreciably affect the sensory attributes or tenderness.

To improve the gel properties of liquid whole egg by short-term lactic acid bacteria fermentation

Fermentation, as a simple, safe and environmentally friendly technology, is promising in the modification of proteins. In this study, the liquid whole egg (LWE) was fermented at 37 °C by Lactiplantibacillus plantarum 90 (L. plantarum 90) which the dose of inoculation was about 8 Log 10 CFU mL−1. During the process, the total aerobic mesophilic count (TAM) and the number of lactic acid bacteria (LAB) of LWE increased at 3 h and then decreased, consistent with the changes in protein solubility. Besides, the T2 relaxation time of fermented egg gels moved to low relaxation time (T22 shifted from 2154.44 ms (0 h) to 1232.85 ms (9 h)), indicating that the water retention of fermented egg gels was enhanced. After fermentation, it could be seen intuitively that the porous structure of the gel surface almost disappeared, along with the improved springiness and brightness by texture and color measurement. This study suggested that moderate fermentation (L. plantarum 90, 1% v/v, 9 h) could effectively improve the gel property of LWE, and thus had a potential to expand the application of LWE in the food industry.

Effect of gaseous ozone application during chilling on microbial and quality attributes of pig carcasses.

Ozone application has been suggested as an additional measure to the slaughter animals under hygiene programs. In this study, we determined the efficacy of gaseous ozone applied to pig carcasses during chilling (16 h at 2-5°C). Forty carcasses were allocated to each treatment: control, without ozone application (T1) and 5 ppm gaseous ozone application (T2), divided in two 4-h periods. The carcasses were sampled before and after chilling. The average counts of total aerobic mesophilic (TAM) bacteria before chilling were not different (p = 0.55) between T1 and T2. In turn, after chilling, the ozone-treated carcasses had significantly reduced about 0.4 colony-forming units (CFU)/cm2 of TAM counts (p < 0.001) than the control carcasses. No significant reduction was observed in the number of carcasses positive for Listeria sp. and Escherichia coli after gaseous ozone treatment; while a tendency (p = 0.08) of lower number of Salmonella positive carcasses in T2 was observed. Common macrorestriction (pulsed-field gel electrophoresis) patterns of S. enterica were observed in the carcasses before and after chilling. Pork samples from treated and untreated carcasses with ozone showed no lipid oxidation or altered color and pH. The results indicate that the gaseous ozone in the tested protocol is effective in reducing TAM populations, but not effective in decreasing the number of carcasses positive for E. coli and Listeria sp. Regarding Salmonella, the tendency of positive carcasses reduction may encourage further studies by testing other protocols of gaseous ozone application inside the chilling chamber.

Evaluation of Street Food Safety and Hygiene Practices of Food Vendors in Can Tho City of Vietnam

The objective of this study was to investigate the food safety status of street foods in the city of Can Tho, Vietnam. A total of 410 consumers was interviewed to get an insight into the popular street foods in the studied area. Vietnamese sandwich (34.63%) and sugarcane juice (24.51%) were consumed popularly according to the survey. A total of 263 street food samples (i.e.Vietnamese sandwich, n = 131 and sugarcane juice, n = 132) were collected from different locations such as schools, hospitals, markets, and other locations in four districts (i.e. Ninh Kieu, Cai Rang, Phong Dien and O Mon) of Can Tho city for microbiological analysis. Total aerobic mesophilic counts (TMC), yeast and mold, coliform, E. coli, and Staphylococcus aureus were assessed. Microbial contamination of Vietnamese sandwich was 5.7-9.2 log CFU/g (TMC), 2.0-7.4 log CFU/g (yeast and mold), 2.5-7.9 log CFU/g (coliform), 1.0-5.9 log CFU/g (E. coli), and 1.7-6.6 log CFU/g (Staphylococcus aureus). There was a significant difference in Vietnamese sandwich sampling among districts (p&lt;0.05). In contrast, the contamination of sugarcane juice samples with regards to total aerobic mesophilic counts, yeast and mold, coliform, E. coli, and Staphylococcus aureus were 7.53±0.74, 5.56±0.71, 6.02±1.21, 2.26±1.31, 1.47±0.77 log CFU/mL, respectively. No statistically significant difference (p&gt;0.05) was observed in sugarcane juice samples among districts and locations. The observation of the handling practices of street food vendors showed inadequate hygiene practices, assessment of the street foods safety showed that they do not satisfy the Vietnam hygiene standard of specific foods. These findings give an insight into the safety status of sampled street foods and may provide needed information for Vietnam’s authorities to further improve the safety of street food and create food safety awareness among consumers and handlers, thereby preventing risk to public health.

High pressure processing of licorice drink with respect to quality characteristics, microbial inactivation, and shelf‐life extension

High hydrostatic pressure (HHP) processing of traditional licorice drink with 200–500 MPa, 3–15 min, and 4°C–40°C revealed optimum operational conditions of 500-MPa pressure, 9.90 min and 18.5°C. Shelf-life studies with the optimum HHP settings were conducted for a 25-day storage at 4°C and 22°C. Control samples at 22°C and 4°C were deteriorated on Days 2 and 7, whereas the HHP-processed samples had a shelf life of 25 days. Initial pH, L*, a*, b*, and C* values and glabridin concentration significantly decreased, but conductivity and turbidity values, total mesophilic aerobic count and total mold and yeast count significantly increased, and no significant change was observed for the initial h°, titratable acidity (TA), glycyrrhizin concentration, and sensory properties for the HHP-processed samples during shelf-life studies. Except for vanillic, caffeic, and acetic acids and miristein, no significant change was observed on phenolic compounds and organic acids. Practical applications Due to perishable nature, licorice drink has very short shelf life, and this situation restricts large-scale production and marketing. Heat processing causes degradation on physical and sensory properties of licorice drink. HHP can achieve shelf life extension of licorice drink up to 1 month without a significant adverse impact on most of the quality parameters enabling large-scale production.

Studies on Microbial Quality, Protein Yield, and Antioxidant Properties of Some Frozen Edible Insects.

This research investigated the microbial quality and the protein contents of Thai commercial frozen products of silkworm (Bombyx mori), bamboo caterpillar (Omphisa fuscidentalis), and field cricket (Gryllus bimaculatus). Total mesophilic aerobic counts were about 8-8.4 log cfu/g, while lactic acid bacteria numbers were up to 5.2 log cfu/g samples. Yeasts and mold as well as Enterobacteriaceae numbers were found to be no more than 6.3 and 6.6 log cfu/g, respectively, while Clostridium spp. enumeration detected 3.2-3.6 cfu per gram frozen insect samples. The protein content in cases of cricket and bamboo caterpillar after the Soxhlet defatting method and the Folch lipid extraction combined with isoelectric point precipitation were similar when compared at pH 3.5 or pH 4.5. In contrast, the protein yield from silkworm was higher at pH 3.5 in the Soxhlet defatted sample, as opposed to the Folch method treated sample where higher protein yield was obtained at pH 4.5. Furthermore, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) of field cricket subcritical water (121 or 135°C for 15 or 30 minutes) hydrolysates were also measured on a pilot basis. These tests revealed higher antioxidant activities in treated samples than in the untreated control. The highest DPPH radical scavenging activity and FRAP values were detected in samples treated at 135°C, while the protein content of these samples was lower than that of the untreated control. These results indicate that hydrolytic compounds of proteins and probably other types of cricket materials are possibly involved in the antioxidant activities of the treated defatted cricket samples.

DETERMINATION OF MYCOBIOTA AND MICROBIAL LOADS OF GRAPES GROWN IN BOZCAADA, TURKEY

Bozcaada which is a province of Çanakkale, Turkey, is located between the 390 48 north parallel and 260 east meridians. The largest livelihood of Bozcaada is viticulture. Therefore, in our study, microbial load, and mould diversity of the Çavuş (table) and Karalahna (wine) grapes which are endemic to the island were evaluated, and ochratoxin production potentials of Aspergillus isolates were investigated by HPLC. A total of 6 vineyards with Çavuş and Karalahna grapes were sampled in 2015 and 2016. Total aerobic mesophilic bacteria count of grapes ranged between 0.00 and 4.21 log CFU/g, yeast load between 0.00 and 2.66 log CFU/g and mould load between 1.67 and 3.20 log CFU/g. A total of 2264 mould isolates were taken from samples. All isolates were identified at the genus level. Aspergillus spp. and Penicillium spp. were the most isolated species in 2015, while Alternaria spp. and Cladosporium spp. were the most isolated species in 2016. It was determined that 13.78% (312) of the isolates were Aspergillus spp., 54 of these isolates, have been selected and identified at the species level. Twenty-one of the black Aspergillus isolates were identified as A. niger / A. acidus, twenty-four of them were A. carbonarius and one of them is A. ibericus. The two white isolates were found to be A. candidus, the creamy brownish-spore forming isolate was A. terreus, and three green isolates were identified as A. flavus, A. calidoustus and A. sydowii. Six isolates (4 A. niger, 1 A. calidoustus, and 1 A. sydowii) were producing OTA. The amounts of ochratoxins varied from 0.80 to 74.01 ng/g.

Microbiological and physicochemical quality of strawberries (Fragaria × ananassa) coated with Lactobacillus rhamnosus and inulin enriched gelatin films

Abstract The consumption of probiotic foods has increased in recent years due to consumer concerns related to healthy diets. In this study, strawberries were used as an alternative product to deliver probiotics and the study aimed to investigate the effect of Lactobacillus rhamnosus on microbial and physicochemical quality of strawberries during refrigerated storage. For this purpose, probiotic Lactobacillus rhamnosus and inulin were added to gelatin-based coatings and applied to fresh strawberries. Probiotic survivability, microbial and physicochemical quality parameters of strawberries were monitored during 16 d of refrigerated storage. According to the results, gelatin-probiotic coatings and gelatin-probiotic-inulin coatings increased the shelf-life of strawberries compared to the control. These coatings significantly decreased the weight loss in strawberries and did not change the quality parameters (pH, titratable acidity, and total soluble solids) during storage. Gelatin-probiotic coatings slowed down fungal growth and total aerobic mesophilic counts in strawberries. While the initial count of Lb. rhamnosus was 11 log CFU g−1, it was found as 8.9 log CFU g−1 and 7 log CFU g−1 on the 10th and last day of the storage, respectively. These results revealed that probiotic incorporated gelatin films can be an alternative way to deliver probiotics and improve the shelf-life of perishable fruits.

Effect of gamma irradiation against microbial spoilage of hummus preserved under refrigerated storage.

The current study aimed to evaluate the preservation of hummus packed in laminated pouches to extend its shelf life for a period of 35 d using a combined treatment of gamma irradiation and refrigerated storage. The effects of different irradiation doses (0, 0.1, 1.5 and 2.5 kGy) and refrigeration (4 °C) against microbial spoilage were investigated. Microbial criteria of total mesophilic aerobic counts, lactic acid bacterial counts, and yeasts and molds decreased significantly (P ≤ 0.05) in a dose dependent manner. Furthermore, dose of 2.5 kGy decreased the lactic acid bacteria counts to undetectable levels for the first 10 d of storage. Although microbial load increased during 35 d of refrigerated storage, samples treated with doses of 1.5 and 2.5 kGy showed a good microbial quality that complies with microbial limits set by national and international authorities for ready to eat foods. Furthermore, Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis and coliform bacteria were not detected in the irradiated samples as well as in the controls. It was observed that a dose ≥1.5 kGy combined with refrigerated storage at 4 °C could be used to extend the shelf life of hummus samples in laminated pouches up to 35 d.

Formulation of a Bio-Packaging Based on Pure Cellulose Coupled with Cellulose Acetate Treated with Active Coating: Evaluation of Shelf Life of Pasta Ready to Eat.

An active packaging based on pure cellulose coupled with cellulose acetate coated with layered double hydroxide (LDH), hosting 4-hydroxybenzoate (listed in EC-Directive 10/2011) as an antimicrobial agent, was formulated and realized. The release of 4-hydroxybenzoate ionically bonded to the LDH layers was much slower than the molecule freely dispersed into the coating. The capability of the active packaging to inhibit Pseudomonas, Escherichia coli, Salmonella and Lactic Bacteria was evaluated, as well as the global migration with three different food simulant (i.e., acetic acid at 3% (v/v), ethanol at 50% (v/v) and vegetable oil) that demonstrated, in compliance with the migration limits of the EU regulation, the suitability of the prepared packaging to be employed as food contact material. Ready to east cooked tomato pasta was packaged into the active trays and in uncoated, as control, up to 30 days at 4 °C. Organoleptic characteristics, mold evolution, total mesophilic aerobic counts (TBC), Enterobacteriaceae, Lactic Bacteria and Pseudomonas, and in colony forming unit per gram (CFU/g), showed a significant activity of 4-hydroxybenzoate in increasing the shelf life of the pasta ready to eat.

Can Resveratrol Used in Fish Salami Production as an Antioxidant be an Alternative to Ascorbic Acid?

ABSTRACT The aim of this study was to use resveratrol to prevent and delay the autooxidation process in fish salami and to increase the shelf life of the product. In addition, the antioxidant and antimicrobial effect of this compound was compared with ascorbic acid. It was determined that, depending on the storage period, total volatile basic nitrogen value increased and exceeded 35 mg/100 g, the limit value for consumption at the third month in control (SK: antioxidant-free) group, at the fourth month in the group containing ascorbic acid (SA), and at the fifth month in the group containing resveratrol (SR). The highest total aerobic mesophilic bacteria count at the end of the storage was determined to be in SK group (P < .05). At the third month of storage, total yeast-mold count of SK, SA, and SR groups was 3.35, 2.30, and 2.09 log CFU/g, respectively (P < .05). This study showed that resveratrol was found to be a promising compound to protect the quality and safety of fishery products.

Mathematical modelling and validation of Salmonella enterica growth in sushi exposed to different time-temperature scenarios found in real sushi establishments

In this study mathematical models to predict Salmonella enterica growth in sushi at different temperatures were developed considering data obtained in 26 restaurants in Southern Brazil. The sushi type chosen to develop the models was the one that presented the highest total aerobic mesophilic counts among sushis collected in the establishments. Salmonella was inoculated (2–3 log UFC/g) in this sushi type prepared in the laboratory (pH 4.8; aw 0.98) and incubated under isothermal conditions at 7, 15, 20, 25 and 37 °C. Baranyi and Roberts model was used to describe Salmonella growth curves, generating R2 values of ≥0.98 and RMSE values of <0.24 log CFU/g/h for primary models. Ratkowsky's equation was used in secondary model, generating R2 of 0.99 and RMSE of 0.02 log CFU/g/h. The model validation was simulated under non-isothermal conditions, using the worst-case scenario that was built through data from the environmental conditions and data obtained from the restaurants. The non-isothermal conditions were performed at 36.3 °C for 6 h, 10 °C for 24 h and 29.5 °C for 6 h sequentially, reaching 6.7 log CFU/g of Salmonella and generating RMSE of 0.06 log CFU/g/h, Bias factor of 0.97 and Accuracy factor of 1.03. The negligible growth time (ς) for Salmonella, considering the average of higher distribution temperatures of chosen sushi type (approximately 18 °C), was 8.9 h. However, growth rates of total aerobic mesophilic demonstrated that at 15 °C and 20 °C, the lag phases were approximately 11 and 5 h respectively. Based on these results, we suggest for sushi distribution the use of temperatures of ≤15 °C for 6 h (maximum time of distribution allowed in Brazil) considering the Salmonella growth.