Title : Comparison of bacterial communities in naturally fermented dairy products from Northeastern India and West Africa
Abstract:
Traditional fermented milk products have been essential components of traditional food culture worldwide, including Doi of India, Kindourni, Fanire and Wagashi cheese of Niger and Benin. However, there are limited reports on the differences in bacterial communities that develop during the spontaneous mesophilic fermentation of cow milk across diverse geographical regions. In this study, we employed high throughput amplicon sequencing of the bacterial 16S rRNA gene to examine 44 samples of naturally fermented homemade milk products. We compared the bacterial community structures of these widely consumed foods from Northeast India and Western Africa. The spontaneous milk fermentation in these two geographically isolated regions shared lactic acid bacteria, mainly from Lactobacillaceae (Lactobacillus) and Streptococcaceae (Lactococcus). Indian samples exhibited high bacterial diversity, predominantly featuring Acetobacteraceae (Gluconobacter and Acetobacter) and Leuconostoc. Conversely, West African samples were abundant in Staphylococcaceae (Macrococcus). However, Wagashi cheese from Benin, made by curdling milk with proteolytic leaf extract of Calotrophis procera followed by natural fermentation, primarily contained Streptococcaceae (Streptococcus spp.). Our analysis also identified several potential pathogens like Streptococcus infantarius, an emerging foodborne pathogen which was found in Wagashi samples. An uncultured bacterium from Enterobacteriaceae was present in Kindouri and Fanire samples, and Clostridium spp. was detected in Doi samples from Northeast India. These findings highlight the need to address safety issues related to spontaneous milk fermentation and to develop technological interventions. Designing starter culture consortia for controlled milk fermentation can ensure the sustainable production of uniformly high-quality products with desirable functional and organoleptic properties.
Keywords: Fermented milk products, MiSeq amplicon sequencing, Lactobacillus, Lactococcus, Gluconobacter, Acetobacter, Macrococcus caseolyticus, Streptococcus infantarius
