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Swab samples from cattle and sheep carcasses (120 of each) were tested for Listeria monocytogenes, and 120 slaughterhouse wastewater samples were tested for listeriophages over 12 months (10 samples per month) to note the seasonal distribution. L. monocytogenes and bacteriophage isolates were characterized, and the biocontrol of L. monocytogenes was investigated in meatballs with a phage cocktail. L. monocytogenes was found in 3.4 and 2.5% of cattle and sheep carcasses, respectively. All the isolates were found to harbor hlyA, actA, inlA, inlB, inlC, inlJ, plcA, plcB, fbpA, and fri genes with varied mRNA expression levels by real-time reverse transcriptase PCR analysis. Five isolates did not harbor the vip gene. According to enterobacterial repetitive intergenic consensus PCR, L. monocytogenes isolates were classified into four different groups based on their DNA patterns. The L. monocytogenes isolates were characterized for antibiotic susceptibility; one strain was found to be resistant to five different antibiotic classes. Of 11 lytic listeriophages, two were selected for the cocktail based on their DNA restriction profiles, efficiency of plating, transmission electron microscopy, and in vitro and in vivo analyses. In the biocontrol study, we used a food model that consisted of a novel bacteriophage cocktail in raw meatballs. The highest reduction of L. monocytogenes was recorded as 2.2 log CFU/g at a multiplicity of cellular infection of 4.7 at the end of 1 h. In conclusion, the new bacteriophage cocktail in this study can be considered an efficient biocontrol agent of L. monocytogenes in meatballs.

The aim of this study was to isolate Listeria monocytogenes from chicken neck skins and lytic bacteriophages from poultry slaughterhouse wastewaters, and following the characterization of the isolates, biocontrol of L. monocytogenes was investigated on chicken drumsticks with the isolated phages. L. monocytogenes prevalence was detected 12.3% in the chicken samples and the dominant serotype was determined as 1/2a (92.5%). Expression levels of major virulence genes were revealed by real‐time RT‐PCR. Ten different DNA profiles were detected by ERIC‐PCR fingerprinting. According to the MIC results, LM‐P75 was defined as MDR by showing resistance to antibiotics in six different groups. Besides, five lytic listeriophages were isolated from wastewaters and treated with Cla1 and Sac1. Taking EoP, TEM, in vitro, and in vivo analyses results into consideration, three bacteriophages were used for the biocontrol assay. The application of the bacteriophages on drumsticks achieved a reduction up to 3.3 log CFU/ml in L. monocytogenes count in 3 hr of incubation at 4°C. Practical applications Our results showed that in spite of the developments in hygiene practices during slaughtering, chicken meat is still a potential source for L. monocytogenes. On the other hand, the phage cocktail that used in this study can be an effective tool to reduce L. monocytogenes in chicken carcasses at final wash or at cooling step in poultry slaughtering process, as well as in decontamination of chicken meat parts.

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The aim of this review was to compile the origin and distribution of water kefir, its production, microbial diversity, fermentation dynamics, health effects, and its place in national/international food legislation. Water kefir is a traditional, slightly carbonated fermented beverage with a lactic acid content of up to 2%. It is obtained by fermenting sugar by kefir grains, which are white or yellowish in color and translucent in appearance. The types of microorganisms in the water kefir differ depending on the sugar, carbon sources, and fermentation conditions. It has a complex microbiota mainly consisting of lactic acid bacteria, acetic acid bacteria, and yeasts. In addition, fermented water kefir contains various metabolites, including sugar, fruit-derived components, lactic acid, acetic acid, ethanol, carbon dioxide, mannitol, vitamins, and amino acids such as arginine. As a non-dairy fermented beverage, water kefir emerges as an alternative source of probiotics for individuals with lactose intolerance, people with dairy allergic reactions, and vegan consumers. However, although consumer demands have driven the food industry to increase the production of water kefir, the most common production still relies on the traditional method due to some difficulties in the industrial-scale production process. On the other hand, more in vitro and in vivo studies should be carried out to reveal the health benefits of water kefir.