Halil TOSUN, A. Kemal SEÇKİN, Şahika AKTUĞ GÖNÜL

Acid Adaptation Effect on Survival of Escherichia coli O157:H7 in Fermented Milk Products

The growth and survival of acid-adapted and nonadapted Escherichia coli O157:H7 were determined in strained, set-type, and synbiotic yoghurt and kefir. Acid-adapted or nonadapted E. coli O157:H7 were inoculated into the synbiotic and set-type yoghurt before and after the fermentation process. Survival of the inoculated E. coli O157:H7 in these products was examined during storage at 4 °C. Acid adaptation enhanced the survival of E. coli O157:H7 in kefir and strained yoghurt. Acid adaptation also enhanced the survival of E. coli O157:H7 in set-type yoghurt, which was inoculated after the fermentation process; however, acid-adapted cell inoculation before fermentation did not enhance survival. These observations support the theory that acid adaptation is an important survival mechanism enabling E. coli O157: H7 to persist in fermented dairy products.

Anahtar Kelimeler:

E. coli O157:H7, fermented milk product, acid adaptation

Acid Adaptation Effect on Survival of Escherichia coli O157:H7 in Fermented Milk Products

Keywords:

E. coli O157:H7, fermented milk product, acid adaptation,

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WHO: Report of WHO consultation on “Prevention and control of enterohaemorrhagic Escherichia coli (EHEC) infections. 1997; WHO / FSF /FOS / 97.6 WHO, Consultation and Workshops, Geneva, Switzerland. 2. Doyle, M.P.: Escherichia coli O157: H7 and its significance in foods. Int. J. Food Microbiol., 1991; 12: 289-301. 3. Griffin, P.M., Tauxe, R.V.: The epidemiology of infections caused by Escherichia coli O157: H7, other enterohaemorrhagic E. coli, and the associated hemolytic uremic syndrome. Epidemiol. Rev., 1991; 13: 60-98. 4.
Borczyk, A.A., Karmali, M.A., Lior, H., Duncan, L.M.C.: Bovine
reservoir for verotoxin-producing Escherichia coli O157: H7.
Lancet, 1987; 1: 98-99. 5.
Morgan, D., Newman, C.P., Hutchinson, D.N., Walker, A.M.,
Rowe, B., Majid, F.: Verotoxin producing Escherichia coli O157
infections associated with the consumption of yoghurt. Epidemiol.
Weagant, S.D., Bryant, J.L., Bark D.H.: Survival of Escherichia coli O157 H7 in mayonnaise and mayonnaise-based sauces at room and refrigerated temperatures. J. Food Protect., 1994; 57: 629-631.
Leyer, G.J., Wang, L.L., Johnson, E.A.: Acid adaptation of Escherichia coli O157:H7 increases survival in acidic foods. Appl. Environ. Microbiol., 1995; 61: 3752-3755.
Foster, J.W.: Salmonella acid shock proteins are required for the adaptive acid tolerance response. J. Bacteriol., 1991; 173: 6896- 6902.
Davis, M.J., Coote, P.J., O’Byrne, C.P.: Acid tolerance in Listeria monocytogenes: the adaptive acid tolerance response (ATR) and growth-phase-dependent acid resistance. Microbiology, 1996; 142: 2975-2982.
Buchanan, R.L., Edelson, S.G.: Culturing enterohemorrhagic Escherichia coli in the presence and absence of glucose as a simple means of evaluating the acid tolerance of stationary-phase cells. Appl. Environ. Microbiol., 1996 62: 4009-4013.
Arocha, M.M., McVey, M., Loder, S.D., Rupnow, J.H., Bullerman, L.: Behaviour of hemorrhagic Escherichia coli O157: H7 during the manufacture of cottage cheese. J. Food Protect., 1992; 55: 379-381.
Govaris, A., Koidis, P., Papatheodorou, K.: The fate of Escherichia coli O157: H7 in Myzithra, Anthotros and Manouri whey cheeses during storage at 2 and 12°C. Food Microbiol., 2001; 18: 565- 570.
Spano, G., Goffredo, E., Beneduce, L., Tarantino, D., Dupuy, A., Massa, S.: Fate ofEscherichia coli O157: H7 during the manufacture of Mozzarella cheese. Lett. Appl. Microbiol., 2003; 36: 73-76.
Tosun, H.: Acid tolerance response of some pathogen bacteria and its importance in food industry. PhD Dissertation (in Turkish), Ege Univ., Fen Bilim. Enst. 2003.
Vogel, H.J., Bonner, D.M.: Acetylornithinase ofEscherichia coli: partial purification and some proporties. J. Biol. Chem., 1956; 218: 97-106.
Gibson, G.R., Roberfroid, M.B.: Dietary modulation of the human colonic microbiota: Introducing the concept of prebiotics. J. Nutr., 1995; 125: 1401-1412.
March, S.B., Ratnam, S.: Latex agglutination test for the detection of Escherichia coli serotype O157. J. Clin. Microbiol., 1989; 27: 1675-1677.
Gahan, C.G.M., O’Driscoll, B., Hill, C.: Acid adaptation of Listeria monocytogenes can enhance survival in acidic foods and during milk fermentation, Appl. Environ. Microbiol., 1996; 62: 3128- 3132.
Garren, D.M., Harrison, M.A., Russels, S.M.: Retention of acid tolerance and acid shock responses of Escherichia coli O157: H7 and non-O157: H7 isolates. J. Food Protect., 1997; 60: 1478- 1482.
Leyer, G.J., Johnson, E.A.: Acid adaptation promotes survival of Salmonella spp. in cheese. Appl. Environ. Microbiol., 1992; 58: 2075-2080.
Cheng, H., Chou, C.C.: Acid adaptation and temperature effect on the survival of Escherichia coli O157: H7 in acidic fruit juice and lactic fermented milk product. Int. J. Food Microbiol., 2001; 70: 189-195.
Hudson, L.M., Chen, J., Hill, A.R., Griffiths, M.W.: Bioluminescence: a rapid indicator of Escherichia coli O157: H7 in selected yoghurt and cheese varieties. J. Food Protect., 1997; 60: 891-897.
Guraya, R., Frank, J.F., Hassan, A.N.: Effectiveness of salt, pH, and diacetyl as inhibitors for Escherichia coli O157: H7 in dairy foods stored at refrigeration temperatures. J. Food Protect., 1998; 61: 1098-1102.