The fate of Escherichia coli O157 : H7 in Myzithra, Anthotyros, and Manouri whey cheeses during storage at 2 and 12 degrees C

Myzithra, Anthotyros and Manouri whey cheeses were inoculated the day after production with Escherichia coli O157:H7 at concentrations of approx. 1.8 x 10(6) cfu g(-1) and stored at 2 and 12 degreesC for 30 and 20 days, respe ctively. The pH of the whey cheeses decreased from an initial value of appr ox. 6.20 to 5.83 or 5.60 (Myzithra) 5.75 or 5.20 (Anthotyros) and 5.80 or 5 .30 (Manouri) by the end of the corresponding storage periods at 2 and 12 d egreesC, respectively. Escherichia coli O157:H7 populations in the whey che eses at the end of the 12 degreesC storage period had grown with an increas e of approx. 1.3 log(10) cfu g(-1) E. coli O157:H7 populations in whey chee ses at the end of the 2 degreesC storage period did not grow and decreased with an approx. 2.5 log(10) cfu g(-1) reduction. Results showed that E. col i O157:H7 can grow at 12 degreesC and survive at 2 degreesC storage in Myzi thra, Anthotyros and Manouri whey cheeses, and therefore post-manufacturing contamination with this pathogen must be avoided by employing hygienic con trol programmes such as HACCP. (C) 2001 Academic Press.