Agriculture Reference
In-Depth Information
Chapter 1
Application of Modifi ed Atmosphere
Packaging on Quality of Selected Vegetables:
A Review
1.1
Chemical and Microbiological Parameters
Affecting Shelf Life
The most common persistent organic pollutants (POPs) occurring were Dichloro-
diphenyl trichloroethane (DDT) and its metabolites (found in 21 % of samples
tested in 1998 and 22 % in 1999), and dieldrin (found in 10 % of samples tested in
1998 and 12 % in 1999) while residues of fi ve and more chemicals could be occur-
ring in a single food item (Schafer and Kegley
2002
). Lettuce was shown to have the
highest concentration of fungicides while Swiss chard appeared to have the highest
levels of insecticides. Washing, blanching, and peeling of vegetables led to a
50-100 % reduction in some cases of pesticide levels (Chavarri et al.
2005
).
Cadmium, copper, lead, chromium, and mercury pose an important threat and can
be detected in high concentrations in vegetables (Islam et al.
2007
).
The use of any microbial preventive technique is excluded in the case of mini-
mally processed vegetables because of the serious impact on their quality (Zagory
1999
). Growth in open spaces and postharvest handling create an elaborate spoilage
microfl ora on vegetables due to contact with various types of microorganisms
(Villanueva et al.
2005
). The type of the vegetable can determine both the type of
spoilage and subsequent quality deterioration (Jacxsens et al.
2003
).
Pseudomonas
,
Enterobacter
and
Erwinia
are the predominant species, while Gram
(−)
amount to
80-90 % of bacteria detected (Francis et al.
1999
).
Asparagus, broccoli, caulifl ower, carrot, celery, cherry tomatoes, courgette,
cucumber, lettuce, mushroom, pepper, turnip, and watercress are some of the vege-
tables in which
Aeromonas
spp. was isolated (Merino et al.
1995
). Mushrooms from
retail markets in United States and various produce items sampled from farmers'
markets in Canada were contaminated with
Campylobacter
(Harris et al.
2003
). The
assembly of ready-to-eat (RTE) meals containing beef or other potential carriers of
E. coli 0157
:
H7
combined with raw salad vegetables may lead to their contamination
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