Application of variable number of tandem repeat analysis to determine the origin of S. aureus contamination from milk to cheese in goat cheese farms

The aim of the paper was to evaluate multiple locus variable number tandem repeat analysis and staphylokinase gene amplification to track the origins of Staphylococcus aureus contamination in dairy environments. The diversity of MLVA profiles (58 profiles among 481 strains) allowed identification of several sources of cheese contamination, most often from bulk milk through S. aureus-shedding goat milk and occasionally milking machine or human. The staphylokinase gene was always present in human S. aureus strains, although it was also present in those from S. aureus-shedding goat milks and, to a lesser degree, from bulk milk and cheeses. Contamination may persist over the same year and also over 2 consecutive years.