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

The effect of CO2-enriched atmosphere in combination with either oxygen or nitrogen on the keeping quality of seabass slices stored at 4degreesC was investigated. The inhibitory effect on bacterial growth increased proportionally to the CO2 concentration in the packaging, maximum inhibition being achieved with 100% CO2 (P < 0.05). Seabass slices stored in CO2-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-CO2 atmosphere, suggesting the denaturation of both muscle and pigment proteins by carbonic acid formed. Thiobarbituric acid-reactive substances (TBARS) increased as the CO2 concentration increased (P < 0.05). However, odour, flavour and overall acceptability of CO2-enriched packaged samples, particularly with 80 and 100% CO2, 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% CO2 atmosphere could be extended to more than 20 days at 4degreesC, compared with 9 days for those packaged in air. (C) 2002 Society of Chemical Industry.