Shelf‐life extension of refrigerated seabass slices under modified atmosphere packaging

The effect of CO 2 ‐enriched atmosphere in combination with either oxygen or nitrogen on the keeping quality of seabass slices stored at 4 °C was investigated. The inhibitory effect on bacterial growth increased proportionally to the CO 2 concentration in the packaging, maximum inhibition being achieved with 100% CO 2 ( P  < 0.05). Seabass slices stored in CO 2 ‐enriched atmosphere had lower total volatile base, trimethylamine, ammonia and formaldehyde contents than those stored in air ( P  < 0.05). However, increases in lightness and exudate loss were observed for samples packaged in high‐CO 2 atmosphere, suggesting the denaturation of both muscle and pigment proteins by carbonic acid formed. Thiobarbituric acid‐reactive substances (TBARS) increased as the CO 2 concentration increased ( P  < 0.05). However, odour, flavour and overall acceptability of CO 2 ‐enriched packaged samples, particularly with 80 and 100% CO 2 , were acceptable throughout storage for 21 days. Chemical and microbial changes in all samples were generally in agreement with sensory panel evaluations. The shelf‐life of seabass slices packaged in 80–100% CO 2 atmosphere could be extended to more than 20 days at 4 °C, compared with 9 days for those packaged in air. © 2002 Society of Chemical Industry