Lactic acid bacteria occurring during manufacture and ripening of Provolone del Monaco cheese: Detection by different analytical approaches

Abstract

Lactic acid bacteria occurring in Provolone del Monaco, an artisanal pasta filata cheese produced in Campania (Italy) from raw cows’ milk and without starter addition, were investigated by a combination of conventional and molecular approaches. The microbial community was monitored during a cheese-making process giving rise to a premium quality product. Streptococcus thermophilus and Streptococcus macedonicus prevailed during cheese manufacture and survived along 9 months of ripening, together with enterococci and lactobacilli of the casei group, especially Lactobacillus rhamnosus. Phenotypic and genetic identification of 308 isolates largely reflected the results obtained by 16S rDNA sequencing analysis by polymerase chain reaction-denaturant gradient gel electrophoresis, with the significant exception of Lb. fermentum and four Lb. delbrueckii subspecies that were not detected by cultural methods. Each different analytical approach employed provided useful information. Their combination proved to be suitable to effectively describe the ecosystem of Provolone del Monaco cheese.