Occurrence and diversity of Shiga toxin-producing Escherichia coli (STEC) in Italian Alpine raw milk cheeses and their development in the earlier stages of different cheese-making processes

Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens implicated in diseases including hemorrhagic colitis and hemolytic uremic syndrome. In the last years, an increasing number of STEC infections associated with the consumption of raw milk cheeses have been reported, contributing to raise the public awareness. The aim of this study was to assess the occurrence of STEC biotypes in raw milk cheeses from Italian Alpine region and evaluate the influence of different scalding temperatures on their development. Six out 82 (7.3%) cheeses led to the isolation of E. coli biotypes with different virulence traits (stx1, stx2 and eae genes). To evaluate the impact of scalding temperatures on STEC growth, three E. coli biotypes were spiked into milk (