Lock, J.L. and Board, R,G., 1994. The fate of Salmonella enteriditis PT4 in deliberately
infected commercial mayonnaise. Food Microbiology 11, pgs. 499-504
Summary:
“A total of 30 samples (24 different varieties) of commercial mayonnaise deliberately
inoculated with Salmonella enteritidis PT4 have been studied. The fastest death rate
of the test organism was obtained with a fat-free mayonnaise pH 2.6. There was a
trend indicating that the antimicrobial attributes of mayonnaise were enhanced when
the pH become more acid, especially with acetic acid as the acidulant. The looseness
of the correlation of death rates with pH in the range 4-5 may well reflect the
contribution of the diverse range of ingredients other than acids to the antimicrobial
properties of this commodity. One general statement is possible, in the majority of
mayonnaises S. enferitidis was protected to a limited extent by storage at 4°C viz a viz
storage at 20°C.”
Raghubeer, Errol V., Ke, Jim S., Campbell, Michael L., and Meyer, Richard S., 1994. Fate
of Escherichia coli 0157:H7 and Other Coliforms in Commercial Mayonnaise
and Refrigerated Salad Dressing. Journal of Food Protection, Vol. 58, pgs. 13-18
Summary:
“Commercial mayonnaise and refrigerated ranch salad dressing were inoculated at two
levels with two strains of Escherichia coli 0 157:H7, a non-pathogenic E. coli, and the
non-fecal coliform Enferobacter aerogenes. Results showed that at the high
inoculation level (>106 colony forming units [CFU]/g) in mayonnaise stored at room
temperature (ca. 22” C) both strains of 0157:H7 were undetected at 96 h. At the high
inoculation level, all strains of coliform bacteria tested survived longer in salad
dressing stored at 4°C than in mayonnaise stored at 22°C. The 0157:H7 strains were
still present at low levels after 17 days. The survival time in the low-level inoculum
(lo* CFU/g) study decreased, but the survival pattern in the two products was similar
to that observed in the high-level inoculum study. Slight differences in survival among
strains were observed. The greater antimicrobial effect of mayonnaise may be
attributable to differences in pH, water activity (aW), nutrients, storage temperature,
and the presence of lysozyme in the whole eggs used in the production of commercial
mayonnaise. Coliform bacteria survived longer in refrigerated salad dressing than in
mayonnaise particularly at the high-level inoculum. Both mayonnaise (pH 3.91) and
salad dressing (pH 4.5 1) did not support the growth of any of the microorganisms
even though survival was observed.”
Originally Posted by Jeff
Trigg I looked it up and was surprised at what I found, this was the first one I opened but some of the others said no, so go figure.
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