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Abstract
The present study was undertaken to find out the response
of modified atmospheric packaging on physical attributes
and surface microbial load of litchi fruits during
storage. It was observed that MAP as LDPE film bags
having ventilation of 0.5% and above, reduced the
percent cumulative loss in weight, browning of skin
surface microbial counts. However, higher microbial
counts were observed in hermetically sealed bags and
0.25% ventilated poly bag packaging. Though, minimum
microbial counts were observed in fruits kept as control
but these fruits were of inferior quality due to excessive
browning, desiccation and consequently brittleness
of skin, which resulted in poor marketability of fruits.
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The litchi fruits were hand picked, washed, surface
dried and packed in 1kg capacity LDPE film bags of
200 gauge thickness provided with 0.0, 0.25, 0.5,
1.0 and 2.0% ventilation and stored under ambient
conditions (30-35degreeC, 40-60%RH ). Various storage
attributes i.e. extent of browning, percent CPLW,
marketability, microbial spoilage and other quality
parameters were determined at 0,2,4 and 6 days of
storage according to the methods described by Singh
and Narayana (1995).
Aerobic mesophilic surface microbial load of litchi
fruits was determined at three distinctive stages
i.e. (i) just after harvest, (ii) after washing with
water and (iii) on day of storage. For this, 100g
of litchi fruits were suspended in 100ml of sterilized
water contained in wide mouth sterile glass jars.
Five replications were kept for each treatment. After
putting litchi fruits, the lid was closed tightly
and the jars were shaken well for 1 min. after shaking,
one ml of properly diluted surface washing was plated
on (i) Rose Bengal Chloramphenicol Agar for isolation
and counting of yeasts and moulds and (ii) on Actidione
Agar for bacteria (Collin and Lyne, 1985). Both types
of media plates were incubated at 30+-2degreeC for
72 hr and the average number of microbial colonies
were counted as Colony Forming Units (CFU) per g litchi
fruit and log CFU was determined accordingly. Predominant
yeasts, moulds and bacteria were identified as per
methods described by Collin and Lyne (1985).
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