Microbial Studies of Prepared Curries Stored in Tin Free Steel Cans

Abstract

Apart from the nutrient analysis microbial study is very much essential to know the microbial contamination after storage. So in the present study it is aimed to investigate the microbial contamination in the prepared fish and shellfish curries stored in tin free steel cans. The prepared curries of fish, shrimp, crab and mussel were stored in TFS cans at room temperature (30 plus or minus 2 degree C) for a period of 18 months. During storage the cans were periodically checked in the intervals of 3rd, 6th and12,h months especially the visual signs of internal and external rusting like appearance of can walls, adhesion of product to the can walls and internal rusting. About eight cans were selected at random from each batch processed to different Fo values. Four cans from each batch were incubated at 55 degree C for 4 days and another four were incubated at 37 degree C for 14 days. The incubated cans were opened under aseptic conditions and the samples were transferred to sterile thioglycollate broth tubes. Then a layer of sterile liquid paraffin was applied in each tube so as to create anaerobic condition. The tubes were then incubated at 37 degree C for 48 hrs and observed for any development of turbidity, which indicates survival of microorganisms. Tubes not showing any turbidity were incubated for further 48 hrs at 37 degree C to ascertain the sterility. Besides the above microbiological quality was assessed from the fish, shrimp, crab and mussel curries by standard plate count, total coliform count and total fungal count, according to APHA. The microorganisms are totally absent in the present study for short and longer time storage (3 to 18 months) offish and shellfish curries stored in TFS cans. Apart from that there is no internal and external rusting, texture during the storage period. So it is conform that TFS cans are suitable to store the fish and shellfish products as evidence by no microbial growth and also not affecting the nutritional quality of the stored food.