Microflora of fresh and ice-stored sardines (Sardina pilchardus) from the Moroccan Atlantic coast

Abstract

Sardines (Sardina pilchardus) caught on the Moroccan Atlantic coast (off El Jadida) were examined fresh (February, May and July trials) and after 10 days of storage in ice (July trial). From fresh fish, a total of 193 strains were isolated from the muscle with skin, gills and viscera, whereas from ice-stored fish, 122 strains were isolated from the muscle. Gram-negative bacteria always predominated among the initial flora in all trials. The predominant Gram-negative microflora of the fresh fish consisted of Moraxellaceae (Moraxella sp., Acinetobacter sp., Psychrobacter sp.), Enterobacteriaceae, Pseudomonadaceae (Pseudomonas sp.), and the genera Shewanella and Flavobacterium. The Gram-positive flora was identified as Staphylococcus sp., Micrococcus sp. and coryneform bacteria. Significant seasonal variation in initial flora was not noted. Ice storage allowed the growth of Gramnegative bacteria, with Pseudomonas as the dominant microflora, followed by Shewanella putrefaciens. The present study indicates that Pseudomonas sp. probably contribute to the spoilage of sardines caught in the Atlantic Ocean.