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Cryotolerance of Escherichia coli 0157:H7 in Laboratory Media and Food
Author(s) -
Grzadkowska D.,
Griffiths M.W.
Publication year - 2001
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2001.tb16100.x
Subject(s) - escherichia coli , cold shock domain , food science , biology , shock (circulatory) , enterobacteriaceae , cold storage , microbiology and biotechnology , bacteria , biochemistry , genetics , gene , medicine , horticulture , rna
The present study compared the cryotolerance of E. coli 0157:H7 strains with nonpathogenic strains of E. coli. Cold shocked (exposed to 10°C for 6 h) and non‐cold shocked (held at 20°C) cultures were frozen at ‐18°C for up to 240 h in brain heart infusion broth, apple juice, frozen yogurt, and ground beef. The E. coli 0157:H7 strains showed the greatest cold shock effect and cryotolerance. The cold shocked E. coli 0157:H7 strains showed a 25 to 35% increase in their ability to survive frozen storage for 24 h at ‐18°C compared to non‐cold shocked cells. The corresponding value for non‐O157 strains was only about 5%. The food matrix changed the cold shock response in all investigated strains. The largest cold shock effect was observed with broth cultures. Cryotolerance of E. coli was not observed in frozen yogurt and ground beef. The effect of prior cold shock was most pronounced in E. coli 0157:H7 strains after 24 h of freezing.