Microbiological status of Egyptian prawn.

A total of 110 prawn individuals were collected from different markets at Cairo and Giza Governorates. The average counts of Aerobes, Psychrophiles, Enterobacteriaceae, Coliforms and Staphylococci were 5 x 10(3), 3 x 10(2), less than 2 x 10(2), less than 3 and 2 x 10(2) organisms per gram newly caught prawn sample, respectively. Such counts were significantly increased in samples collected from markets including raw prawn in shell, raw peeled samples and frozen samples either peeled or in shell. Arizona group, Escherichia coli, Enterobacter group, Proteus group, Providencia group A & B, Shigella group and Staphylococcus aureus could be isolated from examined samples with variable percentages. The public health significance of isolated organisms is discussed.

Effect of temperature on initial bacteria of prawn.

This study was carried out to evaluate the effect of heat and cold on the microorganisms existing in prawn. Roasting for 5 min, boiling for 10 min and storage at -18 degrees C for 10, 20 and 30 days were applied on raw prawn to study the effect of each treatment on the bacterial load. The average counts of APC (aerobic plate count) at 25 degrees C and 0 degree C, Enterobacteriaceae, Coliforms and Staphylococci were 1.3 x 10(7), 6 x 10(4), 2 x 10(2) and 3 x 10(3) organisms per gram raw prawn sample, respectively, then reduced to 10(4), 8 x 10(2), 3 x 10(3), less than 3 and 3 x 10(2) organisms per gram roasted prawn in shell, respectively. Such counts were more reduced in roasted peeled samples. Boiling reduced the average counts of APC at 25 degrees C and 0 degrees C, Enterobacteriaceae, Coliforms and Staphylococci from 8 x 10(8), 2 x 10(5) 2 x 10(7), 3 x 10 and 3 x 10(4) organisms per gram raw prawn sample to 2 x 10(5), 3 x 10(3), 2 x 10(2), less than 3 and 4 x 10(2) organisms, respectively. Concerning freezing storage, it could be observed that the average counts of APC at 25 degrees C and 0 degree C, Enterobacteriaceae, Coliforms and Staphylococci were reduced from 4 x 10(7), 5 x 10(5), 3 x 10(5), 10(3) and 3 x 10(2) organisms per gram raw sample to 5 x 10(4), 10(3), 3 x 10(2), 10 and less than 2 x 10(2) organisms per gram after freezing storage for 30 days.