Document Type : Original Article
Authors
1
Faculty of Organic Agriculture, Heliopolis University for Sustainable Development, Bilbies, Cairo Desert Road, Cairo 11785, Egypt.
2
Agricultural Microbiology Department , Faculty of Agriculture, Ain Shams University, Cairo, Egypt.
3
Heliopolis University for Sustainable Development, Faculty of Organic Agriculture, Cairo, Egypt.
Abstract
In this study, human-safe lactic acid microorganisms (LAM) were isolated from food samples to be used as potential additives for human food. Samples from various food sources (artisanal cheeses, fermented chickpeas, fermented rice, natural yogurt, pickles, and raw milk) were used to inoculate de Man, Rogosa, and Sharpe (MRS) and malt agar plates, which were incubated at 30°C for 48 h or 37°C for 72 h to isolate lactic acid bacteria and yeast, respectively. Out of 120 isolates (85 bacteria and 35 yeast), 75 isolates showed γ-hemolytic activity and were considered “Generally Recognized As Safe” (GRAS) isolates. After testing their growth rate under the gastrointestinal tract (GIT) conditions, including acidic pH and specific bile salt concentrations, we selected 30 isolates. Then, we evaluated the fermentative abilities of these 30 isolates on nine types of carbohydrates, their total acidity, and their antagonistic activity against five human pathogens. Based on the results of these tests, four isolates were selected for identification using the Biolog program and 16S rRNA sequencing for bacteria and 18S rRNA sequencing for yeast and found to be Bacillus bingmayongesis (FJAT-13831), Lacticaseibacillus paracasei (R094), Pediococcus pentosaceus (DSM 20336), and one yeast isolate as Saccharomyces cerevisiae (SaCe1 26S).
Keywords
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