EFFECT OF ICE STORAGE ON MICROBIOLOGICAL AND CHEMICAL CHANGES IN SHRIMP AND MELTING ICE IN A MODEL SYSTEM

Abstract

ABSTRACT In ice stored shrimp, Vibrio, Pseudomonas and/or Moraxella‐Acineto‐batter species were initially dombant. After 12–15 days, Vibrio sp. had disappeared and Pseudomonas sp. predominated followed by Moraxella‐Acinetobacter sp. The mean increase in aerobic plate count over this period was 2.2–2.4 log. In the melting ice (drip) Moraxella‐Acine‐tobacter, Pseudomonas, Flavobacterium, Micrococcus, Vibrio, Corynebacterium, Staphylococcus, Alcaligenes and yeasts were present initially. After 9–13 days, Vibrio, Flavobacterium and Micrococcus sp. could not be detected in the drip, whereas Pseudomonas or Moraxella‐Acinetobacter sp. remained present or in some cases increased. The mean increase in bacterial count of the drip was 3.4 Jog. Considering the loss in TVN in the drip, there was a net increase in TVN ranging from 6.7–60.1 mg N/100g. AA‐N levels in shrimp decreased during storage. The TVN‐AA‐N ratio of drip did not increase significantly until bacterial levels reached 10 per ml drip.