In Vitro Probiotic Characterization and Safety Assessment of Lactic Acid Bacteria Isolated from Raw Milk of Japanese-Saanen Goat (Capra hircus)

Abstract

Two novel probiotic strains of lactic acid bacteria were successfully isolated from the raw milk of dairy Japanese-Saanen goats. Selection criteria for positive candidates were grown on de Man–Rogosa–Sharpe or M17 selective medium at 30, 35, or 42 °C anaerobically, and characterized based on Gram reaction, catalase test, and tolerance to low pH and bile salts. Among the 101 isolated positive candidates, two strains, YM2-1 and YM2-3, were selected and identified as Lacticaseibacillus rhamnosus using 16S rDNA sequence similarity. Culture supernatants of the two strains exhibited antipathogenic activity against Salmonella enterica subsp. enterica serovar. Typhimurium, Shigella sonnei, methicillin-resistant Staphylococcus aureus, methicillin-sensitive Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157. The antipathogenic activities were retained to some extent after neutralization, indicating the presence of antipathogenic substances other than organic acids in the culture supernatants. The two strains were sensitive with coincidental minimum inhibition concentrations (indicated in the parentheses hereafter) to ampicillin (0.25 μg/mL), chloramphenicol (4 μg/mL), gentamycin (4 μg/mL), kanamycin (64 μg/mL), streptomycin (16 μg/mL), and tetracycline (4 μg/mL). Furthermore, the two strains were resistant to clindamycin (16 μg/mL) and erythromycin (4 μg/mL). In addition, both YM2-1 and YM2-3 strains showed less unfavorable activities, including bile acid bioconversion, carcinogenic-related enzymes, mucin degradation, plasminogen activation, and hemolysis, than the detection limits of in vitro evaluation methods used in this study. In summary, L. rhamnosus YM2-1 and YM2-3 are highly safe and promising probiotic strains applicable in the dairy industry, and were first isolated from the raw milk of Japanese-Saanen goats.

Antibiogram profiles of pathogenic and commensal bacteria in goat and sheep feces on smallholder farm

“…In this study, bacterial isolates from goat and sheep feces displayed a considerable resistance to gentamicin. Recent studies (Atlaw et al, 2022;Tanaka et al, 2023) have also highlighted the Average resistance (%) of all bacteria tested to each antibiotic class. Statistical significance was tested using one-way ANOVA.…”

Recent Advances in Fermented Milk and Meat Products—Quality, Nutritional Value and Safety

“…This Special Issue included eleven research articles that covered various topics, including an analysis of milk’s microbiological quality and safety in the context of its nutrition and applicability for fermented product production [ 1 , 2 , 3 , 4 ], the development of novel milk- and meat-based food [ 5 , 6 ], the influence of animal nutrition, material chemical composition and applied processing on the nutritional value of final fermented products [ 7 , 8 , 9 ], and the use of raw materials of animal origin as a source of potentially probiotic strains [ 10 ]. In addition, there are also works examining consumer preferences and sensory analyses of novel products [ 6 , 11 ].…”

“…In addition, there are also works examining consumer preferences and sensory analyses of novel products [ 6 , 11 ]. In this Special Issue, goat’s milk turned out to be an attractive raw material in the context of its microbial profile [ 4 , 10 ] but also its chemical composition [ 8 , 9 ]. In addition, this Special Issue also describes the studies of milk from various breeds of cows and other species, including human milk, but also material at various stages of maturity [ 1 , 4 ].…”

“…The research was carried out using high-throughput, omics techniques [ 1 , 8 ]. What is more, in vitro but also in silico analyses are used to assess the safety of microbial proteins and strains [ 1 , 10 ].…”

“…Japanese-Saanen goats milk is also a source of probiotic strains that were thoroughly characterized by Tanaka et al [ 10 ]. Among the 101 isolated positive candidates, two strains, YM2-1 and YM2-3, were selected and identified as Lacticaseibacillus rhamnosus using 16S rDNA sequence similarity.…”