TITLE:
Influence of the Backslopping Practice on the Microbial Diversity of the Lactococcus Population in a Model Cheesemaking
AUTHORS:
Yann Demarigny, Marion Dalmasso, Aline Tonleu, Véronique Rigobello, Eric Beuvier, Maï Huong Ly-Chatain, Yvette Bouton
KEYWORDS:
Backslopping, Natural Whey Starter, Model Cheesemaking, Lactococcus
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.2 No.6,
August
4,
2011
ABSTRACT: The objective of this work was to study the microbial diversity of natural whey starters (NWS), with a special focus on Lactococcus strains, during 10 successive days of backslopping. Each day, whey samples were enumerated for their Lactococcus, Enterococcus, Leuconostoc and Lactobacillus levels. The diversity and dynamics of the Lactococcus population in whey were investigated using phenotypic methods such as acidifying aptitude and enzymatic activities. Molecular approach using REP-PCR, ERIC-PCR, plamid profiles, phages and prophages research and PFGE was also applied. Lactococci were the main population in whey. Strains from raw milk were sub-dominant. Based on PFGE and phenotypic results lactococci in whey displayed a more heterogeneous phenotype and pulsotype which may reflect greater variations than previously observed within starter. No phages and prophages were spotted on. Plasmids did not seem to be exchanged from strain to strain. The backslopping practice seemed to allow the strains of the starter to rapidly acquire a specificity of their own. The changes observed presumed a slow adaptation of the strains to the “back- slopping environment”. The study of NWS diversity constitutes an important step for the comprehension of acidification defects that recurrently occur in cheesemaking technologies using the backslopping practice.