Molecular identification and typing of lactic acid bacteria associated with the production of two artisanal raw milk cheeses

Abstract

A polyphasic approach was used to evaluate the diversity and persistence of lactic acid bacteria (LAB) strains during the production and ripening of two Flemish artisanal raw milk Gouda-type cheeses, Bellie and Dulses. During two consecutive productions with a one-month interval, samples of milk, starter, curd and cheese at various ripening times were sampled for conventional culturing using four different selective media. The resulting set of 734 isolates was identified using (GTG)5-PCR fingerprinting and sequence analysis of the 16S rRNA and pheS genes. Isolated LAB mainly consisted of Lactobacillus paracasei, Lactococcus lactis subsp. lactis, Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus brevis, Lactobacillus rhamnosus, Lactobacillus curvatus, Enterococcus faecalis, Enterococcus durans and Lactobacillus perolens. A combined typing approach including (GTG)5-PCR and amplified fragment length polymorphism (AFLP) analysis revealed the presence of a Lc. lactis subsp. lactis isolate of the starter in ripened cheese at eight weeks and the persistence of several other LAB strains throughout the two successive production batches. Possibly, a number of these strains are autochthonous members of the microbial cheese production environment that play an important role in the development of the sensory properties of the cheese.