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

Abstract

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, respectively. The pH of the whey cheeses decreased from an initial value of approx. 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 degreesC, respectively. Escherichia coli O157:H7 populations in the whey cheeses at the end of the 12 degreesC storage period had grown with an increase of approx. 1.3 log(10) cfu g(-1) E. coli O157:H7 populations in whey cheeses 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. coli O157:H7 can grow at 12 degreesC and survive at 2 degreesC storage in Myzithra, Anthotyros and Manouri whey cheeses, and therefore post-manufacturing contamination with this pathogen must be avoided by employing hygienic control programmes such as HACCP. (C) 2001 Academic Press.