Carnobacterium spp. in seafood packaged in modified atmosphere

The composition of lactic acid population in five kinds of seafood (salmon,tuna, shrimps, swordfish and cuttlefish) packaged in two different modified atmospheres,MAP1 (80 O2/20 N2) and MAP2 (40 CO2/60 N2), at 4 °C for 6 days was investigated. The isolates were heterofermentative rods belonging to Carnobacterium, Lactobacillus, and cocci of the Leuconostoc genus. The determination of phenotypical characters and a new polymerase chain reaction primer were used to distinguish Carnobacterium from Lactobacillus. The microorganisms found varied with the kind of seafood and the gas composition of the modified atmospheres: in MAP1, richer of oxygen than MAP2, Carnobacterium spp. represents the prevalent microbial group, especially in tuna, shrimps and swordfish, whereas MAP2 seems to favour Lactobacillus spp. Cocci, belonging to Leuconostoc spp., were dominant in salmon and cuttlefish independently of gas composition.