Microbiological quality of some iced fishes of Imphal market, Manipur

Imphal is the main marketing centre of fish in Manipur. As fish production of the state is not sufficient to meet the demands, about 120 metric tons of iced fishes are annually brought from other states and sold in this market. Microbiological quality of iced Wallago attu, Labeo rohita, L. gonius and Aorichthy aor in respect of total fungal count (TFC), total plate count of bacteria (TPC), Most Probable Number (MPN) of coliforms, Streptococci, Staphylococcus, Salmonella and Escherichia coli in four tissues (skin, muscle, gill and intestine) were analysed. In all cases, the counts were highest in the gills and lowest in the muscles. The values of TFC, TPC, coliforms, Streptococci and Staphylococci were 0-10³/g 10(sup)6-10⁸/g, 2-α/g, 10-10⁵/g, 10-10⁵/g respectively. E. coli and Salmonella were not detected in any of the samples while the ice used in the preservation contained 10⁵-10⁷ of TPC per gram. The microbiological qualities of the iced fishes of Imphal market were adjudged poor. The extremely high counts of bacteria might be due to (1) poor quality and left over fishes being packed, (2) contact with contaminated ice and (3) repeated thawing and freezing during the process of marketing and transportation.

Preparation of an extruded fish snack using twin screw extruder and the storage characteristics of the product

A value-added extruded fish product was prepared with corn flour (80%) and fish (sciaenid) powder (20%), using a twin-screw extruder. The effect of different parameters like moisture, temperature, fish powder concentration, speed of the extruder and die-diameter on expansion ratio and crisp texture were studied. The storage characteristics of the final product were studied using three different types of packaging under nitrogen flushing. The study revealed that aluminum foil is the best packaging material to keep the product acceptable for more than three months.

Hydrobiology of Colombo (Beira) Lake, 1. Diurnal variations in temperature, hydrochemical factors and zooplankton

An extensive study of the hydrobiology of the Colombo Lake was initiated by the authors in May 1969 as a contribution to the International Biological Program (Productivity of freshwater communities) by the Department of Zoology, Vidyalankara University of Ceylon, Kelaniya. The Colombo Lake often referred to as the Beira Lake covers an area of approximately 160 acres. The water is usually very turbid with a greenish blue appearance due to the presence of large quantities of blue green algae.