Microbiological and Sensory Evaluation of Fresh Fish Packaged in Carbon Dioxide for Retail Outlets in the Midwest

Abstract

Fresh fish obtained from a commercial packaging plant were evaluated for microbial content and sensory changes during 3 weeks of storage. Fish were packaged in (a) nylon-Surlyn bags and backflushed with approximately 80% CO₂, (b) in nylon-Surlyn bags with no alternation of gaseous environment, or (c) over-wrapped with polyvinyl chloride film. After packaging, fish were stored at 1°C. Two types of fish (ocean perch and sea trout) were analyzed. The data indicate that fish packaged in the nylon-Surlyn bag with CO₂ had the smallest increase in microbial numbers followed by the fish packaged without CO₂. An increase in the bacterial lag phase was observed for the fish packaged in CO₂ when compared with fish packaged without CO₂ or over-wrapped. The fish packaged in CO₂ maintained a lower pH during storage compared with fish packaged without CO₂. The highest microbial load was found in fish packaged with the polyvinyl chloride over-wrap.