Biomedical Engineering Reference
In-Depth Information
inspection survey (2001-2010). The cumulative study revealed that the aerobic
colony counts for the RTE product groups were as follows: from 106 to 108 CFU/g
for 50 % of sandwiches; under the detection limit (<10 CFU/g) for 88.6 % of oven
baked pastries; <10
5
CFU/g for 86.5 % of desserts oven baked; from 10
3
to 10
9
CFU/g
for desserts with dairy cream. The highest mean
Enterobacteriaceae
counts were
recorded for desserts with dairy cream. The highest percentages of foodborne
pathogens were:
Listeria monocytogenes
(20 %) and
Staphylococcus aureus
(12.5 %) in desserts with dairy cream;
Salmonella
spp. (17.5 %) and presumptive
Escherichia coli
O157 (8.5 %) in sandwiches and
Bacillus cereus
(14.6 %) in oven
baked pastries. Aerobic colony counts were in the range of 10
7
-10
8
CFU/g for
48.8 % of frozen pastries; whereas
Enterobacteriaceae
counts between 10
3
and
10
4
CFU/g were detected in 35.3 %. Foodborne pathogens prevalence for frozen
pastries were as follows:
B. cereus
(31.8 %),
Salmonella
spp. (28.6 %), presumptive
E. coli
O157 (25 %),
S. aureus
(8.7 %) and
L. monocytogenes
(8.7 %).
A bacteriological assessment of the food products at different stages of process-
ing was conducted during the manufacturing of ready-to-eat (RTE) chicken franks,
chicken bologna, and bacon at a large meat processing plant in Trinidad, West
Indies.
Staphylococcus aureus
was the most common pathogen detected in pre-
cooked products (mean counts 0.66, 1.98, and 1.95 log10 CFU/g for franks, bolo-
gna, and bacon, respectively). This pathogen was also found unacceptable levels in
4 (16.7 %) of 24 post-cooked samples. Fifty percent (10 of 20) of precooked mix-
tures of bacon and bologna were contaminated with
Listeria
spp., including four
with
L. monocytogenes
. Pre-cooked mixtures of franks and bologna also contained
E. coli
(35 and 0.72 log10 CFU/g, respectively) while 5 (12.5 %) of 40 pre-cooked
mixtures of chicken franks had
Salmonella
spp. Aerobic bacteria exceeded accept-
able international standards in 46 (82.1 %) of 56 pre-cooked and 6 (16.7 %) of 36
post-cooked samples. Both pre- and post-cooking air and processing surfaces had
relatively high levels of aerobic bacteria,
Staphylococcus aureus
and coliforms,
including equipment and gloves of employees. A drastic decrease in aerobic counts
and
Staphylococcus aureus
levels was observed after heat treatment, thus subse-
quent increase suggests that there is a post-cooking contamination. A relatively high
level of microbial contamination risk exists for RTE meats at the processing plants
(Syne et al.
2013
).
Irawati et al. (
2007
) investigated the effect of irradiation at medium doses in
combination with cryogenic condition to ensure the safety, quality and shelf-life of
prepared meals. Semi-concentrated black, ox-tail, chicken vegetable and chicken
sweet corn soups were individually packed in a dry laminate pouch of PET 12
μ
/
LDPE and 2
. The product under vacuum
packed was subjected to freezing for 24 h at −18 °C prior to irradiation doses of 1,
3, 5 and 7 kGy at cryogenic condition (−79 °C), respectively. Both the non-irradiated
and irradiated meals were then stored in refrigerator at 5 ± 2 °C. Non-irradiated and
irradiated samples at 1 kGy were mostly spoiled after a week of storage. Gamma
irradiation at doses of 5-7 kGy for the soups could reduce microbial load by 2-3 log
cycles, without affecting the physico-chemical parameters and palatability. The
storage life of irradiated product was 2-3 months, while the un-irradiated samples
could store only for 1 month.
μ
/Al-foil 7
μ
/LDPE adh/LLDPE (C
4
) 50
μ
