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FATE OF LISTERIA MONOCYTOGENES IN CARRA CHEESE DURING MANUFACTURE AND RIPENING
Author(s) -
DURMAZ H.
Publication year - 2009
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.2009.00154.x
Subject(s) - ripening , listeria monocytogenes , food science , raw milk , listeria , cheese ripening , biology , bacteria , genetics
Carra cheese produced from raw milk is a traditional cheese that contains mostly black cumin ( Nigella sativa ) and is produced in the Southeastern provinces of Turkey. This study was carried out to evaluate the growth and survival of Listeria monocytogenes during manufacture and ripening of Carra cheese. For this purpose, Carra cheese was produced with raw cow's milk inoculated to contain 2.97 log cfu/mL of L. monocytogenes (serovar 4b). Cheese was ripened through storing in an earthenware jug underground for 90 days. Enumeration of L. monocytogenes was made by surface‐plating on Oxford agar. The number of L. monocytogenes increased during manufacture and reached 4.89 log cfu/g at the first day of ripening, while it decreased to 4.19 log cfu/g during the first 15 days of ripening and remained constant throughout the rest of the ripening period. The results indicated that L. monocytogenes in Carra cheese manufactured with raw milk was able to survive for 90 days of ripening despite low pH and the presence of a high number of lactic acid bacteria. Thus, Listeria ‐contaminated Carra cheese could cause serious illness if consumed by susceptible individuals.PRACTICAL APPLICATIONS Behaviour of L. monocytogenes during manufacture and ripening of different types of cheese in several countries should be studied in order to determine the exact risk that this food represents to food safety. Considering the processing method (it was prepared with raw milk) of Carra cheese and that artisan practices may still be applied under potentially poor hygienic conditions in small dairies, there is a potential for L. monocytogenes in the cheese at the time of consumption. Therefore, this study was undertaken to describe what might be expected if Carra cheese is manufactured from contaminated raw milk. In Carra cheese, the pathogen might survive after ripening for 90 days. Therefore, we think that individuals should be consuming Carra cheese with caution. Otherwise, Listeria ‐contaminated Carra cheese may cause serious and mortal illnesses, even outbreaks, in humans.