Agriculture Reference
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for 9 days (Cliffe-Byrnes et al.
2003
). The rate of deterioration on sensory scores
was signifi cantly greater at 8 °C with PA fi lms scoring signifi cantly higher than
OPP. The Weight loss was considerably higher in air and statistically greater at
8 °C. Although it may not seem to be the best option, packaging within microperfo-
rated fi lms allowed better preservation of quality.
The effect of chlorine treatment (washing in a 100 ppm chlorine solution for
5 min) and PMAP (microperforated OPP fi lms PA-160 and PA-210 used) on cole-
slaw mix stored at 4 and 8 °C for 9 days was monitored by Cliffe-Byrnes and
O'Beirne (
2005
). Chlorine washed coleslaw at 4 °C remained within sensory
acceptable limits throughout the storage period. Chlorine also reduced the initial
counts of
Pseudomonas
species, at both 4 (7.05 and 7.04 log CFU/g) and 8 °C (7.3
and 7.33 log CFU/g) for both fi lms (PA-160 and 210). PA-160 with chlorine wash-
ing at 4 °C was found to be the best combination.
Coleslaw mix inoculated with
L. monocytogenes
and two strains of
E. coli
and
stored afterwards under passive MAP (OPP fi lm) at 4 and 8 °C for 12 days was
analyzed by Francis and O'Beirne (
2001
).
L. monocytogenes
numbers was shown to
decrease by 1.5 log cycles during storage at 8 °C, and by approximately 2.0 log
cycles when samples were held at 4 °C. Populations of
E. coli O157
:
H7
on coleslaw
mix increased by approximately 1.5 log cycles by day 5, whereas they declined by
1 to 2 log cycles, depending on strain, with further storage at 8 °C.
Francis et al. (
2007
) focused on the contribution of the glutamate decarboxylase
(GAD) acid resistance system to survival and growth of
L. monocytogenes
LO28 in
PMAP (OPP 35
m) coleslaw stored at 4, 8 and 15 °C for 12 days. A wild strain of
L. monocytogenes
and 4 strains with mutant genes (
ʼ
ʔ
gadA,
ʔ
gadB,
ʔ
gadC,
ʔ
gadAB) of negligible GAD activity were inoculated on the coleslaw. At 4 °C, the
populations of the
gadAB (2.7 log CFU/g) were lower than the wild-type or other
strains (about 4.1 log). At 15 °C, the order of survival was LO28 >
ʔ
ʔ
gadA >
ʔ
gadC
>
ʔ
gadB >
ʔ
gadAB.
1.8
Conclusions
According to the already previously presented experimental researches, the ability
of different packaging conditions to delay the quality loss of the vegetables was
explained. Factors such as storage temperature, use of several pretreatments, fi lm
permeability or light and dark storage conditions combined with atmosphere modi-
fi cation led to shelf life extension. Shelf life extension achieved on chicory endive
varied from 2 to 3 days. A 14 to 60-day storage life was observed in tomato samples
stored under MAP. Carrots stored under MAP remained edible from a time period
of 7 to 15 days, while broccoli under MAP gained a 7 to 14-day storage period elon-
gation. For 7 to 14 days mushrooms that underwent MAP storage were organolepti-
cally acceptable, while 28 days was the shelf life limit for asparagus in MA packages.
Postharvest quality of peppers was maintained for 15 to 28 days by altering the in-
package atmosphere and lettuce preservation reached 10 days under MAP. A sum-
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