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Behaviour of four diarrheagenic E scherichia coli pathotypes on carrots and in unpasteurized carrot juice
Author(s) -
GómezAldapa C.A.,
TorresVitela M. del R.,
AcevedoSandoval O.A.,
RangelVargas E.,
VillarruelLópez A.,
CastroRosas J.
Publication year - 2013
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.12145
Subject(s) - pasteurization , carrot juice , food science , escherichia coli , daucus carota , biology , fruit juice , microbiology and biotechnology , horticulture , biochemistry , gene
The behaviours of Shiga toxin‐producing Escherichia coli ( STEC ), enteroinvasive E. coli ( EIEC ), enteropathogenic E. coli ( EPEC ) and enterotoxigenic E. coli ( ETEC ) strains on raw carrots at 3 ± 1 and 30 ± 1°C, and in unpasteurized carrot juice at 3 ± 1, 12 ± 1, 20 ± 1, 30 ± 1°C and 37 ± 1°C were determined. Raw carrots were purchased in a local market. Fresh juice was obtained from raw carrots in the laboratory. On whole carrots stored at 30 ± 1 or 3 ± 1°C, no growth was observed for any of the diarrheagenic E. coli pathotype ( DEP s) strains studied. After 15 days at 30 ± 1°C, the tested DEP s had decreased from an initial inoculum level of approximately 6 log colony‐forming units ( CFU ) to approximately 3·5 log CFU on whole carrots, while at 3 ± 1°C, they decreased from approximately 2·4 log to 1·6 log CFU . All these DEP s grew in fresh carrot juice at 12 ± 1, 20 ± 1, 30 ± 1 and 37 ± 1°C, reaching counts of approximately 4·2 log, 5·8 log, 6·7 log and 7·5 log CFU ml −1 , respectively, after 24 h. At 3 ± 1°C, the DEP growth was inhibited at least during 7 days. Thus, storage of carrot juice at unrefrigerated temperatures can result in DEP growth to levels likely to represent a risk to consumers. Significance and Impact of the Study The information presented shows the potential of Shiga toxin‐producing Escherichia coli , enteroinvasive E. coli , enteropathogenic E. coli and enterotoxigenic E. coli strains for survival on carrots and growth in carrot juice at warmer temperatures. The information can help food processors in plants and restaurants understand the importance of the implementation of hazard analysis and critical control point (HACCP) strategies for preventing potential diarrheagenic E. coli pathotypes (DEPs) contamination and growth in carrot juice. This is the first report regarding the behaviour these DEPs on carrots and in carrot juice.