ESTUDO DA INFLUÊNCIA DE PSICROTRÓFICOS AERÓBIOS E DE ...

varieties marketed in Portuguese supermarkets, were analysed. To evaluate the growth
potential of L. monocytogenes, 27 selected samples were inoculated with two Listeria
serovars, 1/2a and 4b. The number of cells/g present in the day of inoculation and in the last
sell-by-date day were determined and compared.
A taste panel laboratory evaluation to know the salad’s sensorial changes during this period
was realized by paired organoleptic tests, to assess the changes dimension that reaches the
consumer at the end.
The psychrotrophs and Enterobacteriaceae average contamination levels were, respectively
per gram of salad, 2,44 x 10 7 and 2,28 x 10 6 . These values indicate a high hygienic
contamination, which recommends attention by the process manager of these products, for
safety and as well for quality assurance reasons. On top of this, was found that native
contamination by Listeria monocytogenes was present but only in one of the screened
samples (1, 5 %). Despite this, it was verified that the growth of spiked serovars of
L. monocytogenes, was not supported by the salads assayed and the numbers of native
micro flora present, seemed to have no relationship with this fact. Nevertheless, the results
of sensorial analysis showed that organoleptic differences occurred during the storage
period.
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