Quality Indicators of Northern Shrimp (Pandalus borealis)

Qingzhudifferent electrochemical gas sensors (Dräger, Germany, CO, H 2 S, and SO 2 ; CityTechnology, U.K., NH 3 ) and a temperature sensor. Electronic, and A/D converter, and amicroprocessor to read the measurements and send them to the computer are also in thebox. A fan is positioned in the container to ensure gas circulation. The measurementtechnique was reported earlier by Olafsdottir et al. (1997a). 500 g. of shrimp wereanalyzed; the measurement time was 5 min and temperature was 7-9 o C during themeasurements.Figure 3: Electronic nose FreshSense used to measure quality change of shrimp.3.12 Bacteriological testThe total viable counts (TVC) was performed according to the Compendium of Methodsfor the Microbiological Examination of foods published by the American Public HealthAssociation (APHA 1992). The samples of whole shrimp for bacteriological analysis toestimate total viable counts (TVC) were first minced. This procedure was then followedby weighing 25 g of each the minced sample, homogenizing it in 225 g of dilution buffer.1 ml of the primary 1/10 suspension was then withdrawn and decimal dilutions wereprepared in dilution buffer. Total viable counts were done on agar containing 0.5% NaClby pour plate and incubated at 22°C for 72 hrs for psycrotrophic bacteria. Theconventional "pour-plate" method was used. Plates showing colony numbers of 25 to 250were then selected for counting. The number of colonies counted thus constituted thetotal viable counts (TVC).UNU-Fisheries Training Programme 16