Document Type : Research article
Authors
1
Dairy Science and Technology Department, Faculty of Agriculture & Natural Resources, Aswan University, Aswan, 81528, Egypt.
2
Dairy Science and Technology Department, Faculty of Agriculture and Natural Resources, Aswan University, Aswan, Egypt.
3
Dairy Science Department, Faculty of Agricultre, Al-Azhar University, Cairo, Egypt.
4
The Regional Centre for Mycology and Biotechnology (RCMB), Al-Azhar University, Cairo, Egypt.
Abstract
Kefir is a traditional fermented dairy product characterized by a diverse microbial community and recognized for its potential health-promoting properties. This investigation aimed to assess the probiotic attributes of Russian kefir milk produced under Egyptian conditions, using both conventional kefir grains and a starter culture derived from strained kefir. Analyses focused on microbial populations—including lactic acid bacteria (LAB) such as Lactobacillus and Streptococcus/Lactococcus species—yeasts, and total viable counts, as well as physicochemical properties such as pH, moisture, and protein content. Probiotic tolerance was also evaluated under conditions simulating gastrointestinal stress, including exposure to acidic pH, bile salts, and simulated gastric and intestinal fluids. Both fermentation methods yielded high levels of viable microorganisms, with LAB concentrations of approximately 10⁸ CFU/mL that remained stable during refrigerated storage. LAB counts consistently exceeded 8 log CFU/mL, while yeast populations increased from approximately 4–5 log to 5–6 log CFU/mL by the end of the storage period. Notably, coliforms were absent in all tested samples. These findings confirm that kefir functions as a natural probiotic food. Future studies are warranted to investigate kefir’s potential health benefits, such as antimicrobial and anticancer effects, as well as to refine fermentation parameters for improved sensory quality.
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