Effect of modified atmosphere packaging on the survival of Yersinia enterocolitica in Indian oil sardine

Abstract

Modified atmosphere packaging (MAP) is commonly used preservation method to extend the shelf life of fishes. Although MAP is widely used for fishes, the report on the optimum gas composition for Yersinia enterocolitica is very scant. Hence, the present work was undertaken to assess the survival of Y. enterocolitica exposed to different gas composition. For this, Y. enterocolitica at 105 cfu g-1 was inoculated on to sardine (Sardinella longiceps) and packed in polyester-polyethylene laminated pouches. The packs were divided into 7 lots. One lot was used as control air pack and for other 6 lots, different combinations of carbon dioxide and oxygen were flushed before sealing the pouches. All the packs were stored on ice and the survival of Y enterocolitica, total aerobic plate counts and biochemical quality was monitored at regular intervals. Total volatile base nitrogen content increased with the storage period, which correlated well with the total aerobic plate counts. The gas combination of 80 colon 20 exhibited better inhibitory effect for Y. enterocolitica compared to other gas compositions. The use of MAP with combination of 80 colon 20 can be used for extending the shelf life of perishable food commodities like fishes significantly which helps in expanding the marketing of fishes to distant locations with maximum control with respect to major food borne pathogens.