Survival of Listeria monocytogenes during the manufacture and ripening of Turkish white cheese.

Listeria monocytogenes was enumerated during the manufacture and ripening of Turkish White cheese with particular reference to a) pasteurized milk, b) cheese milk after inoculation with L. monocytogenes (0 h), c) after curd formation (2 h), d) curd after pressing (6 h), e) curd after pH was reduced (17 h), f) curd after salting (32 h), and g) cheeses during ripening. Cheeses were also examined periodically for total solids, moisture and salt contents, pH values and aerobic plate count. An increase in the number of L. monocytogenes was observed during manufacture. Following salting and throughout the storage period, numbers of L. monocytogenes decreased at a rate depending on the salt concentration, starter activity and storage time. The initial microbial number had a significant (P < 0.01) effect on the survival of L. monocytogenes during the storage period.