Objective
:
The aim of the present study is to evaluate the presence of
Salmonella
spp. and
Listeria
monocytogenes
in ready-to-eat foods by comparing the performance and sensitivity of BIO-RAD commercial
Kits based on real-time PCR detection with traditional culture (ISO) procedures.
Materials and methods
:
Sixty-five samples of ready-to-eat foods were analysed as described above. In order
to verify the validity of both culture and biomolecolar methods and to compare the sensitivity of real-time
PCR versus conventional culture (ISO) procedures, five food samples were artificially contaminated with the
Salmonella enteritidis
ATCC strain by using scalar concentration from 10
3
to 10
-
1
cfu/g while one food sample
was artificially contaminated with the
Listeria monocytogenes
ATCC strain. Finally, statistical analyses of the
results were performed using the statistics “K” to confirm the agreement between the compared methods.
Results:
Both procedures showed the absence of
Salmonella
spp. and
Listeria monocytogenes
in the
processed samples; results in agreement appeared both for the five food samples artificially contaminated
with
Salmonella enteritidis
ATCC strain and for the food sample artificially contaminated with
Listeria
monocytogenes
ATCC strain. The sensitivity of the biomolecolar test was 1 cfu/g
. Therefore full agreement
between the two methods was detected, with a K value of 1.
Conclusions:
The real-time PCR system appears to be extremely useful in the rapid screening of food
samples, allowing for the rapid identification of
Salmonella
spp. and
L. monocytogenes