Total Aerobic Mesophilic Bacteria Research Articles

Effect of UV-C Irradiation and High Hydrostatic Pressure on Microbiological, Chemical, Physical and Sensory Properties of Fresh-Cut Potatoes

UV-C irradiation and high hydrostatic pressure (HHP) successfully reduce the number of bacteria and their growth but can also affect phenolic and sugar content, as well as other physicochemical properties. Therefore, in this work, the effect of UV-C irradiation, HHP, and their combination, UV-C/HHP, on total aerobic mesophilic bacteria count (TAMBC), chlorogenic acid and sugar content, and other physicochemical properties of raw FCP were examined. Acrylamide and polycyclic aromatic hydrocarbons (PAH) were also monitored in treated FCP after frying. Vacuum-packed potato slices pretreated with an antibrowning agent were irradiated with UV-C (2.70 kJ m−2), treated with HHP (400 MPa/3 min) and combined UV-C/HHP, and stored for 15 days. The greatest reduction in TAMBC was achieved in the UV-C/HHP-treated samples, followed by the HHP treatment, and they both resulted in the slowest bacterial growth during storage. All treatments decreased the contents of chlorogenic acid, but the greatest reduction was observed in the HHP-treated samples. All treatments increased the content of reducing sugars, and UV-C/HHP did so significantly, which also led to an increase in acrylamide content in the fried FCP. PAH levels were below the established limits. Acceptable sensory attributes of all samples (raw, boiled, and fried) remained relatively stable during storage.

Effect of coating with chitosan enriched with different borates on the shelf life of fish fillet.

In this study, the effects of biofilm coatings obtained by immobilization of different borates - namely borax (BX), colemanite (COL), and ulexite (UX) - with chitosan (Ch) on the shelf life of rainbow trout fillets were investigated. The immobilization and characterization of borates in Ch were confirmed by scanning electron microscopy, Fourier transform infrared spectroscopy, and zeta potential analysis. In determining the shelf life of fillets that were covered by immersion and stored for 15 days, microbiological (total aerobic mesophilic, psychrotrophic, lactic acid, Pseudomonas, and Enterobacteriaceae bacteria counts) and chemical analyses (total volatile basic nitrogen, thiobarbituric acid reactive substance, and pH levels) were performed at 3day periodic intervals. In addition, the biodegradation of borates was determined using inductively coupled plasma mass spectrometry in biofilm-coated fillets on the 1st, 8th, and 15th storage days. The microbial results of the coatings enriched with borates (BX, COL, and UX) at different levels (0, 0.03, and 0.06 mg L-1 ) (due to the immobilization with Ch) show the shelf life was extended by 3-6 days in all of the treatment groups compared with the control. It was concluded that BX, COL, and UX coatings enriched by immobilization with Ch increase shelf life and improve fillet quality. In addition, the enrichment of BX, COL, and UX with Ch showed explicit natural protective effects. This study demonstrates that Ch-enriched coatings of BX, COL, and UX can be used as natural bioactive nanocarriers to provide bioactive food ingredients in the seafood processing industry. © 2023 Society of Chemical Industry.

Comparison of Dry and Wet De-Feathering Methods on the Quality Characteristics and Shelf Life of Broiler Carcasses

In poultry slaughterhouses, carcasses can be contaminated with microorganisms at various points during the slaughtering processes, affecting some quality characteristics and shelf life of chicken meat. The present study was conducted to investigate the effects of different de-feathering methods on the meat quality characteristics and shelf life of broiler chickens. Forty male broilers 42 days of age (Ross 308) were used in the experiment. After slaughtering, they divided into 2 groups and first group was de-feathered by simple dry plucking method (DPM) and the other was a classic wet method (CWM). 5 fillets and 5 drumsticks from each treatment group were analyzed 0, 3, 5, and 7th days of storage time. The water holding capacity (WHC), color, pH and Warner-Bratzler shear force value (W-BSFV) were analyzed for meat quality characteristics of the raw meat samples. Total aerobic mesophilic bacteria, total psychrophilic bacteria, numbers of microorganisms assessed critically for food safety such as coliform bacteria, E. coli, Enterococcus spp. Campylobacter spp. also, the presence of Salmonella spp. in carcasses was determined. The results indicated that the skin colors of the fillets and drumsticks were yellower and the meat color of the drumsticks was darker in the DPM group than CWM. On the other hand, no significant effects of the plucking method were detected on the WHC and W-BSFV of the samples. The pH value of the fillets was higher in CWM group (P<0.01), but there were no differences between the pH values of drumsticks of two groups. The microorganism levels, however, were influenced significantly (P<0.01) by the plucking methods and the storage time. The shelf life of the carcasses was shortened, due to the high microbial load in DPM group. It is concluded that simple DPM may be used by low capacity farms which produce the broilers for consumers who prefer yellow-skinned chicken meat at the expense of reduction in the shelf life due to increased microbial load.

Shelf life modelling of kaşar cheese packaged with potassium sorbate, nisin, silver substituted zeolite, or chitosan incorporated active multilayer plastic films

The effects of active films on the stability of kaşar cheese stored at 5 °C, 15 °C, and 25 °C were investigated regarding microbial quality, physicochemical, and textural properties. The antimicrobials incorporated into the films (LDPE/polyamide/LDPE+2% antimicrobials) were potassium sorbate (PS-film), nisin (N-film), chitosan (CTS-film), or silver substituted zeolite (AgZeo-film). Shelf life, activation energy, and temperature quotient were also calculated. According to total mesophilic aerobic bacteria (TMAB) count, active films successfully inhibited microbial growth. The lowest growth rate for TMAB count of the samples was found in AgZeo-film, followed by N-film. CTS-film was more effective in controlling total yeast and mould count. PS-film showed some inhibition ability in both counts, but not as much as the other active films. Hence, antimicrobial agents incorporated into active films should be chosen considering main deteriorative microorganism in food being packaged. The active films improved shelf life of kaşar cheese by lasting the lag times of microorganisms.

Impact of sanitizer application on Salmonella mitigation and microbiome shift on diced tomato during washing and storage

This study examined the shift in Salmonella and indigenous microbiota on diced tomato after washing with three different sanitizers and during post-wash cold storage. Roma tomatoes were inoculated with a Salmonella cocktail (initial level ∼ 5.6 CFU g−1), diced and washed along with uninoculated diced tomato in simulated flume wash water with sanitizers, including 10 mg L−1 free chlorine (FC10), 90 mg L−1 peracetic acid (PA90), PA90 in combination with a proprietary acidified surfactant blend (PS90), and unsanitized control (CK). Salmonella, total mesophilic aerobic bacteria (MAB), and yeast and mold (YM) populations on both inoculated and uninoculated samples were measured before and after washing, and during storage at 4 °C. 16S rRNA amplicon sequencing was also performed to determine the shift in bacterial microbiome. Washing with all tested sanitizers, especially PS90 (> 4 log Salmonella reduction), reduced Salmonella and MAB populations on inoculated diced tomatoes. Additionally, application of sanitizers mitigated Salmonella cross-contamination onto uninoculated samples. PS90 treatment inhibited the proliferation of most dominant bacteria on diced tomatoes during storage, including Erwiniaceae, Curtobacterium, Pantoea, Erwinia and Enterobacterales, which may benefit product quality and safety.

Effect of non-thermal ultraviolet and ultrasound technologies on disinfection of meat preparation equipment in catering industry.

In recent years, ultraviolet and ultrasound treatments are gaining attraction as promising green decontamination technologies to ensure microbial safety in food industry. Decontamination by ultraviolet light is a physical process defined by the transfer of electromagnetic energy from a light source to an organism's cellular material and depended on the emission of radiation in the ultraviolet region (100-400 nm), specifically the UV-C region (200-280 nm) which has been demonstrated to be germicidal. Ultrasound technology is defined as sound waves with high and low frequency beyond the limit of human hearing and shows a decontamination effect that occurs as a consequence of cavitation at high power (low frequency) in general. In the present study, it was aimed to determine the effectiveness of ultraviolet light (254 nm, 10 min) and high frequency ultrasound techniques (40 kHz, 10 min) in reducing total aerobic mesophilic bacteria, yeast and mold, Esherichia coli/coliform and Salmonella spp. on the equipment surfaces used in the catering facility. For this purpose, the equipment (cutting knife, meat grinder knife, knife sharpener, cut-proof glove) used in the meat preparation department of catering facility were selected for the treatments. According to the results, appreciable reductions were achieved in total aerobic mesophilic bacterial counts of the ultraviolet treated samples (maximum difference 2.61 log cfu/cm2) and the ultrasound treated samples (maximum difference 4.07 log cfu/cm2). After ultraviolet treatment, Salmonella spp. were totally inhibited on the contaminated surfaces. Furthermore, Escherichia coli/coliform was not detected in the samples after both treatments whereas it was detected before the treatments. It has been concluded that the techniques are effective in reducing microbiological load and also ultraviolet treatment is effective on pathogenic microorganisms on food contact surfaces. As a result, the ultraviolet and ultrasound techniques are effective treatments for equipment disinfection in the catering sector and can be used industrially as it gives successful results.

Production and evaluation of microbiological & rheological characteristics of kefir beverages made from nuts

Herein we report the preparation of nut milks followed by kefir production from Almond, peanut, hazelnut, walnut, and cashew. Nut-based milks were used to make kefir from 100% vegetable milk without food additives or sugar. During 30 days of storage at 4 °C, the microbiological (total aerobic mesophilic bacteria, lactobacilli, lactococci, acetic acid bacteria, yeast) and rheological (apparent viscosity, consistency constant, flow behavior index, thixotropy) parameters of kefir samples made from cow's milk and nut-based milk were monitored and compared to examine the effects of different milk types and storage time. The titratable acidity value of nut kefirs was lower than cow kefir. Kefir from walnut milk had the lowest titratable acidity value (0.15%), lowest apparent viscosity (3.3 mPa s) and consistency coefficient (682.1 mPa.sn). Titratable acidity values of the samples increased while apparent viscosity, thixotropy, flow behavior index and consistency coefficient decreased during storage. According to the power-law model, the kefir samples exhibited non-Newtonian pseudoplastic flow behavior. The apparent viscosity values of peanut and almond kefirs were higher among the prepared samples (p < 0.05). The total number of aerobic mesophilic, lactic acid and acetic acid bacteria of kefir samples decreased during storage, while the number of yeasts increased. Kefir made from cow's milk had the highest average total aerobic mesophilic bacteria, lactococci, lactobacilli, and acetic acid bacteria counts, whereas kefir made from peanut milk had the highest yeast count (p < 0.05). During storage the lowest decrease (%) in the counts of microorganism was determined in almond kefir (4.06%), followed by cow (5.16%), walnut (5.73%), peanut (6.72%), cashew (7.78%), and hazelnut kefirs (9.53%).

Effects of dietary thyme and rosemary essential oils on performance parameters with lipid oxidation, water activity, pH, colour and microbial quality of breast and drumstick meats in broiler chickens.

This study was aimed at determining the effects of different doses of thyme essential oil (TEO) and rosemary essential oil (REO) incorporated into broiler rations on performance parameters, including body weight gain, feed intake and feed conversion rate, as well as on the quality criteria of breast and drumstick meat. The study material comprised of 400 three-day-old male Ross 308 chicks, which were assigned to five groups, each of 80 broilers. Each group was divided into four sub-groups of 20 animals. In this study, the feed rations provided to the control group and groups TEO-150, TEO-300, REO-100 and REO-200 were supplemented with 0, 150 mg kg TEO, 300 mg kg TEO, 100 mg kg REO and 200 mg kg REO, respectively. Fattening performance parameters were statistically similar in the control group and all trial groups ( ). It was determined that, while dietary supplementation with TEO and REO significantly reduced total mesophilic aerobic bacteria (TMAB) counts throughout storage in drumstick meat and on days 0 and 8 of storage in breast meat ( ), it showed variable effects on other microbial counts and during other time points in both breast meat and drumstick meat. Dietary supplementation with TEO and REO was ascertained not to affect the pH value of breast and drumstick meat and to show limited and variable effects on colour parameters and water activity throughout the storage period of breast and drumstick meat. In all groups supplemented with TEO and REO, the thiobarbituric acid reactive substance (TBARS) levels of drumstick meat were observed to have significantly decreased on days 0, 2 and 4 of storage ( ). As a result, dietary supplementation with TEO and REO was determined to have a limited effect on performance parameters, but to improve the microbial quality of meat.

Physicochemical and microbiological properties of Kavılca Bulgur (A traditional cereal product of Turkey

Kavılca bulgur is a cereal product that is obtained from Kavılca wheat grown as a wheat type in Kars province and its surroundings. 40 unpackaged bulgur samples were used in this study and these samples were produced with traditional methods at family businesses under home conditions in Kars province and sold at delicatessens, grocery stores, and arcade marketplaces.&#x0D; In this study, which was carried out to determine the compliance of some microbial and physicochemical properties of Kavılca bulgur with the Turkish Food Codex Wheat Flour Communiqué and the Turkish Food Codex Microbiological Criteria Regulation, the samples were examined in terms of color, ash, moisture, pH, % titratable acidity (as sulfuric acid) and Total Aerobic Mesophilic Bacteria (TAMB), coliform, yeast-mold and rope-spore numbers&#x0D; Ash, moisture, and % titratable acidity ratios of Kavılca bulgur samples were found within the limits specified in the Turkish Food Codex Notification on Wheat Flour.&#x0D; According to the results of the microbiological analysis, the yeast-mold, coliform bacteria, and rope numbers were found to be within the range of the maximum acceptable limit stipulated in the Turkish Food Codex Regulation on Microbiological Criteria.&#x0D; We can say that it is important to develop and support the cultivation of Kavılca wheat, which has high nutritional value and can be utilized in various ways.&#x0D; Keywords: Bulgur; Kavılca; Microbial and physicochemical properties; Traditional cereal

Determination of some quality properties and antimicrobial activities of kombucha tea prepared with different berries

Kombucha is a slightly sweet, acidic, carbonated, fermented beverage obtained by fermenting sugared tea (Camellia sinesis) with symbiotic bacteria. In the present study, kombucha was produced from black tea (Camellia sinensis), black grape (Vitis labrusca), black mulberry (Morus nigra), and rosehip (Rosa canina) fruits. Its physicochemical, microbiological, sensory properties and antimicrobial effects were investigated. During the fermentation, pH, Brix (%), viscosity, total antioxidant, and phenolic substance values decreased (p < 0.05). Total aerobic mesophilic bacteria (TAMB) and yeast/mold, Lactococcus/Streptococcus counts decreased, while the osmophilic yeast, acetic acid, and lactic acid bacterial counts increased (p < 0.05). The samples produced using black mulberry had the highest antibacterial activity (26.58 mm zone diameter), lowest minimum inhibitory concentration (MIC) (0.012 mg·L$^{-1}$), and minimum bactericidal concentration (MBC) (0.008 mg·L$^{-1}$) on Staphylococcus aureus. The highest antifungal activity was in the rosehip on Mucor racemosus (p < 0.05). The a* values increased during fermentation, while L* and b* values decreased. Based on the sensory analysis, black mulberry was the most preferred sample concerning all assessment criteria.

Microbiological quality of some fresh wild edible mushrooms

Fresh mushrooms are an ideal medium for microbial growth because they have high moisture content and a neutral pH. Mushrooms are hand-harvested and exposed to ambient conditions until commercialised in many cases. These characteristics limit their post-harvest shelf life to a few days. Unlike other fresh products, the studies on the microbiological profile of fresh mushrooms are limited. In public, Lactarius species are known as "çıntar, melki, kanlıca, termite, menne specifically used in Türkiye. These mushrooms usually grow naturally during the autumn. They are collected by locals and sold in public markets and along the roadside. In this study, the microbiological quality of wild edible Lactarius species sold in local marketplaces in the province of Muğla was determined. The results are in the ranges 6.10-8.83 log CFU/g for total mesophilic aerobic bacteria, &lt;1.00-5.57 log CFU/g for lactic acid bacteria, 3.10-7.76 log CFU/g for total yeast, &lt;1.00-3.93 log CFU/g for total mould, &lt;1.00-4.74 log CFU/g for Staphylococcus aureus, &lt;0.30-5.07 log MPN/g for total coliform and &lt;0.30-5.07 log MPN/g for faecal coliform. The samples' pH and titratable acidity values were 6.82-7.54 and 0.005-0.020%, respectively.

Toz bebek mamalarının mikrobiyolojik kalitelerinin ve mama hazırlama önerilerine uygunluğunun araştırılması

The present study aimed to investigate the microbiological quality of powdered infant formulas on sale in Turkey and to assess the compliance of the preparation instructions recommended by the formula companies with the guidelines of the World Health Organization (WHO). In the study, 36 powdered infant formulas belonging to 10 different companies were analysed regarding the presence of Cronobacter sakazakii, Bacillus cereus, Staphylococcus aureus, coliform and faecal coliform, mould-yeast, total mesophilic aerobic bacteria counts. C. sakazakii was detected in two of the examined formula samples. At various levels, B. cereus in nine, S. auerus in four, coliform bacteria in 10 and faecal coliform bacteria in eight of the formula samples were found and these identified values were discovered above the legal limits. When the compliance of the preparation instructions recommended by the formula companies with the WHO guidelines was evaluated, the instruction requiring the water temperature to be &gt;70°C, which is critical in the control of C. sakazakii, was not included in the preparation instructions of any formula companies. Although the microbiological quality of the formulas was determined by the legal limits, it was observed that the targeted microbiological quality could not be reached in some of the examined formula samples and the instructions prepared by the companies may not be adequate for the food safety.

Comparison of hardaliye produced by different starters: Back-slopping and kombucha

During traditional hardaliye production by fermentation from grape juice, mustard seeds are insufficient to inhibit yeast activities and alcohol formation. Chemical preservatives are used for the production of hardaliye of standard quality in traditional and industrial production. Today, consumers prefer natural products that do not contain chemical preservatives and additives. For this reason, in this study, considering that different production techniques should be tried in order to prevent alcohol formation, hardaliye production was carried out with two different methods as back-slopping (BH) and addition of kombucha mushrooms (KH). These methods were tried for the first time on hardaliye. Fermentation continued for 7 days (d) and storage for 14 d. During fermentation, pH and reducing sugar, L* and a* values of samples decreased, while phenolic compounds’ concentration, viscosity, and b* values increased. The pH continued to drop during storage. No significant changes were observed in reducing sugar contents. During storage, phenolic content of KH sample decreased and viscosity and L* values increased. The titratable acidity increase was greater in BH sample compared to the KH sample. While 5.5% alcohol formation was observed in the BH sample on the 7th day of fermentation, no alcohol formation was detected in the KH sample At the end of fermentation and storage, Total mesophilic aerobic bacteria (TMAB), yeast, Lactobacillus spp. and lactic streptococci numbers were found to be higher in BH sample than in KH sample. According to the results of the research, thanks to the metabolic activities of the kombucha mushroom microorganisms and their symbiotic association, natural fermentation takes place without any preservative chemicals in KH and more durable hardaliye production is provided compared to BH.

Potential environmental and human health risks caused by heavy metals and pathogens from illegal landfill sites in Bosnia and Herzegovina

In Bosnia and Herzegovina, several illegal waste dumps pose a significant threat to soil and water contamination. The aim of this study was to determine the levels of heavy metal contamination of soils and microbiological contamination of water near investigated landfills. The goal was to identify the harmful effects of illegal landfills on the environment and public health, as well as assessing the potential of contaminants to pollute soil and water resources. Using an Atomic Absorption Spectrometer, the amounts and distribution of four heavy metals (Cd, Co, Pb, and Cr) in soil at four illegal landfills in Central Bosnia were studied. Three water samples collected near the dumpsites studied were tested for microbes. Bacteriological analyses of water included determination of total mesophilic aerobic bacteria, aerobic heterotrophic bacteria, total coliform and fecal coliform bacteria and fecal enterococci. Quantitative results were analyzed using an analysis of variance and Tukey HSD post hoc test. Concentrations of Cd (4.96 mg/kg) and Pb (206.97 mg/kg) recorded in soil at particular sites were above the limits of maximum allowable concentration. Cr and Pb values in soil samples were relatively higher on average than that of Cd and Co. Enrichment factor and pollution load index indicated high concentration of heavy metals in soil, especially Cd. Based on these results, waste from illegal landfills may release considerable amounts of harmful metals and microbes into the environment.

Characterization of physicochemical, rheological, aroma, and sensory properties of spreadable processed cheese supplemented with chia, quinoa, and teff seeds

The physicochemical, rheological, aroma, and sensory properties of spreadable processed cheese supplemented with chia, quinoa, and teff seeds were evaluated. The changes in proximate composition, color values, rheological parameters, volatile profile, sensory, and microbiological properties of the cheese samples stored at 4 °C for 90 days were assessed. Significant differences in the initial contents of dry matter, protein, and fat were observed among the cheese samples. The pH was affected by the storage time and type of added pseudocereal. Moreover, the storage time and type of pseudocereal interaction affected the titratable acidity and color parameters of the cheese samples. The water-soluble nitrogen content increased slightly in all cheese samples during storage. The cheese samples supplemented with pseudocereals exhibited a pseudoplastic behavior. The consistency index of the cheese samples ranged from 2.277 to 2.550 Pa.sn, and the flow behavior index ranged from 0.528 to 0.665. The counts of total coliform and yeast-mold in all cheese samples were &lt;1 log CFU/g cheese, and the counts of total mesophilic aerobic bacteria ranged from 2.21 log CFU/g cheese to 2.76 log CFU/g cheese. A total of 27 volatile compounds, consisting of acids, aldehydes, ketones, esters, and terpenes, were identified in the cheese samples. The amounts of butanoic acid, hexanoic acid, octanoic acid, and nonanoic acid in all cheese samples were higher than that of other volatiles, with the amounts ranging from 639 µg/kg to 3284 µg/kg, 711.20 µg/kg to 2723.27 µg/kg, 187.60 µg/kg to 722.71 µg/kg, and 75.42 µg/kg to 206.02 µg/kg, respectively. The most preferred cheese in terms of sensory properties was the control sample, followed by the SCT, SCQ, and SCC samples.

The effects of heat treatment on chemical, biochemical, and microbiological properties of Ezine cheese

In this study, Ezine cheese was manufactured in accordance with different heat treatment norms (at 65 °C for 10, 20 and 30 minutes) and ripened for 180 days. Different heat treatment norms did not affect the chemical composition of the cheeses, while statistically significantly affected the water-soluble nitrogen (WSN) and 12% trichloroacetic acidsoluble nitrogen (TSN-SN) ratios. Although pH and protein were reduced during ripening, titration acidity, moisture, WSN, TCA-SN and amino acid ratio increased. αs1-casein was more hydrolyzed than β-casein during ripening in Ezine cheese. The heat treatment time increased, while the counts of total aerobic mesophilic bacteria and Escherichia coli decreased.

Investigations on the shelf life of rainbow trout fillets covered by quinoa biofilms enriched with different essential oils (Nigella sativa and Mentha piperita).

Having no adverse effects on the consumer's health, causing zero or minimal damage to the environment, and maintaining the nutritional quality of the product are too important criteria for food packaging materials. Edible biofilm packaging techniques are successful to meet many of these features. To strengthen this claim, rainbow trout (Oncorhynchus mykiss) fillets were coated with an edible film solution (obtained from quinoa starch), which attracted a lot of attention in terms of nutritional value. The prepared biofilm solutions were applied in four different groups (control, quinoa, quinoa + black seed oil, and quinoa + mint oil) and stored in refrigerator conditions (4 ± 1 °C) for 15 days. Microbiological (total aerobic mesophilic bacteria, psychrophilic bacteria, Pseudomonas, lactic acid bacteria, and Enterobacteriaceae) and chemical analyses (TBARS, TVB-N, pH) were performed on certain days of storage. At the end of the study, it was stated that coating fish fillets with edible quinoa, which was enriched by black cumin and mint essential oils, had positive chemical and microbiological results. The highest value for pH was 7.03 ± 0.09 obtained in the control group. It was found that black seed oil has antimicrobial specifications via slowing the microorganism development and prolongs the storage time. The TVB-N value was below the consumable limit value (25 mg/100 g) in the treatment groups and the TBARS value was lowest (1.62 ± 0.21 μmolMA/kg) in the black seed oil group. Consequently, it is suggested that black seed oil may be used on trout fillets to prolong storage time.

Marinasyon öncesinde pişirme işlemi uygulanan kalamar halkalarının toplam mezofilik aerobik ve laktik asit bakteri sayılarını tahmin etmek için modellerin geliştirilmesi

This study was conducted in order to develop different statistical models for estimating the bacterial count of squid rings marinated with lemon juice and mineral water after cooking. The marination ratios and times were as follows: (10:90; 90:10; 50:50; 100:100/100 g squid ring) and (1, 3, 6, 12, 24, 48 and 72 h), respectively. The effects of marination ratios and times on the microbiological and sensory changes of the cooked squid rings were observed at 4°C. Pathogenic bacteria (Vibrio spp., Staphylococcus aureus and Escherichia coli) were not found in the cooked (C) and cooked marinated (CM) squid rings in the present study. The TMC (total mesophilic aerobic bacteria counts) of all groups were determined as consumable at 72 h, whereas the TMC of C and CM samples (C7, CM7, CM14, CM21, CM28) increased to 5.92, 5.83, 5.71, 5.57 and 5.42 log cfu/g, respectively. Regression models were created to estimate the TMC and lactic acid bacteria count (LBC) of cooked squid rings during the marination process at 4°C to determine the increasing rates of bacterial growth of samples. As a result of this study; when compared with Model I and Model II; both of them can be preferred for predicting the TMC of C and CM samples. The variability in the TMC of C and CM squid samples was obtained as 93% in Model I, whereas the variability in the TMC of these samples was observed as 91% in Model II. So, these two models performed well, and they can be used for predicting the TMC of C and CM samples. Additionally, Model III was also developed for estimating the prediction value of LBC of cooked squid samples during the marination process at 4°C. This model was also determined very good performance (86%) to estimate the predicting values of LBC and it can be very essential together used with Model I or Model II for marinated fishery products to estimate the real shelf-life.

Hydrogen-Rich Water Can Restrict the Formation of Biogenic Amines in Red Beet Pickles

Fermented foods are considered the main sources of biogenic amines (BAs) in the human diet while lactic acid bacteria (LAB) are the main producers of BAs. Normal water (NW) and hydrogen-rich water (HRW) were used for preparing red beet pickles, i.e., NWP and HRWP, respectively. The formation of BAs, i.e., aromatic amines (tyramine, 2-phenylethylamine), heterocyclic amines (histamine, tryptamine), and aliphatic di-amines (putrescine), was analyzed in both beet slices and brine of NWPs and HRWPs throughout the fermentation stages. Significant differences in redox value (Eh7) between NWP and HRWP brine samples were noticed during the first and last fermentation stages with lower values found for HRWPs. Total mesophilic aerobic bacteria (TMAB), yeast–mold, and LAB counts were higher for HRWPs than NWPs for all fermentation stages. Throughout fermentation stages, the levels of all BAs were lower in HRWPs than those of NWPs, and their levels in brines were higher than those of beets. At the end of fermentation, the levels (mg/kg) of BAs in NWPs and HRWPs were, respectively: tyramine, 72.76 and 61.74 (beet) and 113.49 and 92.67 (brine), 2-phenylethylamine, 48.00 and 40.00 (beet) and 58.01 and 50.19 (brine), histamine, 67.89 and 49.12 (beet) and 91.74 and 70.92 (brine), tryptamine, 93.14 and 77.23 (beet) and 119.00 and 93.11 (brine), putrescine, 81.11 and 63.56 (beet) and 106.75 and 85.93 (brine). Levels of BAs decreased by (%): 15.15 and 18.35 (tyramine), 16.67 and 13.44 (2-phenylethylamine), 27.65 and 22.7 (histamine), 17.09 and 21.76 (tryptamine), and 21.64 and 19.5 (putrescine) for beet and brine, respectively, when HRW was used in pickle preparation instead of NW. The results of this study suggest that the best method for limiting the formation of BAs in pickles is to use HRW in the fermentation phase then replace the fermentation medium with a new acidified and brined HRW followed by a pasteurization process.

Toplu Yemek Üretimi Yapan Bir İşletmede Personel ve Gıda Temas Yüzeylerinin Mikrobiyolojik Yönden Değerlendirilmesi

Bu çalışmada, Kayseri ilinde bir kamu kuruluşuna ait toplu yemek üretimi yapan bir tesiste yemek hazırlamada çalışan personel ve gıda ile temas eden yüzeylerden alınan örneklerin bazı indikatör mikroorganizmaların varlığı açı- sından incelenmesi amaçlandı. Çalışma süresince tesis Nisan-Temmuz 2021 tarihleri arasında birer ay arayla dört kere ziyaret edildi. Her ziyarette tesiste yemek hazırlamada çalışan 24 personel ile 16 adet ekipman ve gıda ile temas eden yüzeylerden (bıçak, köfte şekillendirme makinesi, kıyma makinesi, et doğrama makinesi, sebze doğrama makinesi ve tezgâh) alınan svap örnekleri materyal olarak kullanıldı. Alınan örnekler toplam aerobik mezofilik bakteri (TAMB) sayımı ile koliform, Escherichia coli (E. coli) ve Staphylococcus aureus (S. aureus) kontaminasyon durumu bakımından kon- vansiyonel metotlar kullanılarak analiz edildi. Çalışmada, analiz edilen personel el svap örneklerinin %6.6, %3.3 ve % 4.4’ü sırası ile S. aureus, E. coli ve total koliform ile kontamine olduğu belirlendi. Tesiste yemeklerin hazırlık aşamala- rında çiğ gıda ile temasta olan yüzey örneklerinin tamamının total koliform ve E. coli, %96.8’inin ise S. aureus ile konta- mine olduğu tespit edildi. Çalışma sonuçları, Kayseri ilinde bir kamu kuruluşunda toplu gıda üretimi yapılan tesiste çalı- şan personelin büyük çoğunluğunun el hijyeni kurallarına uyduğunu fakat yemek hazırlama aşamalarında kullanılan ekipman ve yüzeylerin sanitasyonunun yetersiz olduğunu ve çapraz kontaminasyon riski taşıdığını gösterdi.