Growth of Aeromonas hydrophila and Pseudomonas tragic on Mince and Surimis Made from Atlantic Pollock and Stored Under Air or Modified Atmosphere

Abstract

Mince, salt-added surimi, and low-salt surimi prepared from Atlantic pollock had different protein, NaCl, and carbohydrate levels. Samples of these products were steamed, cooled, and coinoculated with Aeromonas hydrophila and Pseudomonas fragi. Jars containing modified atmosphere (MA)-stored samples were flushed so that initial headspace composition was 51% N₂, 13% O₂, and 36% CO₂. These, and samples under air, were incubated at 5 and 13°C. Headspace composition of sample jars determined throughout storage at 5°C indicated that greater growth occurred on air-stored mince and low-salt surimi than on air-stored salt-added surimi, or on MA-stored samples. Colony counts of both species were appreciably reduced by the MA storage. In addition, the high salt level of salt-added surimi decreased growth of both species, although A. hydrophila was affected more than P. fragi. Results indicated that A. hydrophila was quite capable of competing with P. fragi on mince and low-salt surimi stored under air or MA at both 5 and 13°C.