Survival of some pathogens in local Urfa cheese during the ripening period in 90 day

uı SURVİVAL OF SOME PATHOGENS İN LOCAL URFA CHEESE DURING THE RİPENİNG PERYOD İN 90 DAY (M. Sc. Thesis) Ebru YILMAZ GAZI UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY SEPTEMBER 2002 ABSTRACT In this research, the presence and the survival of Eshehchia coli OibtMt Salmonella enteritidis, Shigella flexneri, Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus were studied in Urfa cheese, a local cheese, produced from pasteurized milk. For this purpose Esherichia coli O157.H7, Salmonella enteritidis, Shigella flexneri, Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus were added into the milk to be used in making cheese. Half of the produced cheese were boiled. Produced cheese were stored for ripening for 90 day in pickling solutions with 3 different salt concentrations.(%12,5, %15, %17,5). During the ripening period, in week zero and day 7, 14, 30, 60, 90 specimens were collected and examined microbiologycally for Esherichia coli Om:H7, Salmonella enteritidis, Shigella flexneri, Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus, Aerob mesophilic general viable, Lactobacilli and Yeast. At zeroth day in groups 1 and 2 while Staphylococcus aureus were 4,1x103cfu/ml average the count were found to be lower than zeroth day in 90 day (2,3x1 03cfu/ml). Bacillus cereus were found during the ripening period (in 90 day) at the cheese samples, tn which hadIV received thermal boiling process and other group (hadn't received thermal boiling process). Esherichia coli Ois?:H7wem found dosing the ripening period but in Urfa cheese which had received thermal boiling process were found day 14 the last Yersinia enterocolitica were not found all of the cheese samples during the ripening period and Yersinia enterocolitica count were found to be lower the lest period than day Oth. Salmonella enteritidis were found at tfe cheese samples only %12,5 salt conservation during the ripening period. Salmonella enteritidis were not found during 90 day, other cheese samples and like Yersinia enterocolitica, Salmonella enteritidis count were found to be lower the lest period than day 0th. Shigella flexneri were found at the cheese samples %12,5 and %15 salt concentration during the ripening period. Shigella flexneri count while were found 3,0x1 03cfu/rnl average in Otf day, at 14th day were found 2,0x1 03cfu/mi. Total mesophilic bactery, yeast, total coliform bactery and lactic acid bacteria counts were to be lower in 90 day than 0th day. Science Code : 401.01.04 Key words : Cheese, brine, survival, Esherichia coli Oi&Hr, Salmonella enteritidis, Shigella flexneri, Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus. Page Number : 86 Adviser : Assist Prof. Dr. Güven URAZ