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GROWTH OF ESCHERICHIA COLI O157:H7 IN THE PRESENCE OF PSEUDOMONAS FLUORESCENS IN SKIMMED MILK AT 7 OR 25C
Author(s) -
QUINTO E.J.,
FRANCO C.M.,
FENTE C.A.,
VAZQUEZ B.I.,
CEPEDA A.
Publication year - 1997
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.1745-4565.1997.tb00168.x
Subject(s) - pseudomonas fluorescens , incubation , escherichia coli , skimmed milk , bacteria , food science , population , incubation period , microbiology and biotechnology , chemistry , biology , biochemistry , medicine , genetics , environmental health , gene
Escherichia coli O157:H7 STCC 4076 , E. coli O157:H7 STCC 4267 and E. coli STCC 515 were cultured alone or in combination with Pseudomonas fluorescens STCC 378 at 7C or 25C in 10% reconstituted skimmed milk. Culture pH and bacterial population densities were monitored over 40 days. Both E. coli O157:H7 strains grew well after 40 days of incubation at 7C with final pH values between 4.86–4.53. At 25C, both E. coli O157:H7 strains grew during 20 days with final pH values of 4.00–4.14. The pH of the different cultures of this study decreased more at 25C than at 7C. The results suggest that P. fluorescens may inhibit the growth of the other bacteria present in milk at 7C, but this inhibition is weak. In contrast, the growth of E. coli O157:H7 strains in the presence of P. fluorescens appears to be slightly enhanced during most of the incubation period at 25C.