Ravi Sankar C N, Lalitha K V, Jose Leema, Manju S, Gopal T K S
Central Institute of Fisheries Technology, Cochin-682 029, India.
Food Microbiol. 2008 May;25(3):518-28. doi: 10.1016/j.fm.2007.12.003. Epub 2008 Jan 12.
Effect of packaging atmosphere (air and under different modified atmospheres (MAs), 40% CO2/60% O2, 50%/50% O2, 60% CO2/40% O2, 70% CO2/30% O2 and 40% CO2/30% O2/30% N2) on the microbial and biochemical attributes of fresh pearlspot (Etroplus suratensis Bloch) stored at 0-2 degrees C was investigated. Trimethylamine nitrogen (TMA-N) and thiobarbituric acid (TBA) values remained lower than the proposed acceptability limits throughout the storage period. Results demonstrated that storage of pearlspot under air and MA 40% CO2/30% O(2)/30% N(2) resulted in growth of Enterobacteriaceae, Aeromonas and H(2)S-producing bacteria including Shewanella putrefaciens, while all other packaging atmospheres did not allow multiplication of Enterobacteriaceae and Aeromonas within 3 weeks. Aeromonas spp. identified were Aeromonas hydrophila, Aeromonas veronii biovar sobria and A. veronii biovar veronii. Significant reduction (p<0.01) was noticed in Aeromonas population of pearlspot stored under MA 60% CO2/40% O2 and 70% CO2/30% O2. A delay of growth of Pseudomonas below 5.0log(10)cfug(-1) was observed during the 15th day of storage at 0-2 degrees C under modified atmosphere packaging (MAP) conditions. Growth of faecal streptococci was significantly inhibited in all the packaging atmospheres at 0-2 degrees C during the entire storage period. Survival of coagulase positive Staphylococci (<50cfug(-1)) in low numbers was noticed during storage in all the packaging atmospheres. Clostridium botulinum toxin was not detected. All the packaging atmospheres did not allow multiplication of sulphite-reducing clostridia at 0-2 degrees C during the entire storage period. Packaging in MA 60% CO2/40% O2 resulted in the inhibition of growth of Aeromonas and Enterobacteriaceae, and the slowest growth of psychrotrophic bacteria, H(2)S-producing bacteria, including Shewanella putrefaciens and Pseudomonas and extended microbiological shelf life to 9-10 days. This study confirms the survival of potentially pathogenic A. hydrophila, A. veronii biovar sobria and A. veronii biovar veronii capable of growth at low temperature in pearlspot stored under MA.
研究了包装气氛（空气和不同的气调包装（MA），40%二氧化碳/60%氧气、50%/50%氧气、60%二氧化碳/40%氧气、70%二氧化碳/30%氧气和40%二氧化碳/30%氧气/30%氮气）对0-2℃储存的新鲜珍珠斑（Etroplus suratensis Bloch）微生物和生化特性的影响。在整个储存期间，三甲胺氮（TMA-N）和硫代巴比妥酸（TBA）值均低于建议的可接受限度。结果表明，在空气和40%二氧化碳/30%氧气/30%氮气的气调包装条件下储存珍珠斑会导致肠杆菌科、气单胞菌属和包括腐败希瓦氏菌在内的产硫化氢细菌生长，而所有其他包装气氛在3周内均未使肠杆菌科和气单胞菌属繁殖。鉴定出的气单胞菌属菌种为嗜水气单胞菌、维氏气单胞菌温和生物变种和维氏气单胞菌维氏生物变种。在60%二氧化碳/40%氧气和70%二氧化碳/30%氧气的气调包装条件下储存的珍珠斑气单胞菌数量显著减少（p<0.01）。在0-2℃气调包装（MAP）条件下储存的第15天观察到假单胞菌生长延迟至低于5.0log(10)cfu/g。在整个储存期间，在0-2℃的所有包装气氛中，粪链球菌的生长均受到显著抑制。在所有包装气氛储存期间均发现少量凝固酶阳性葡萄球菌存活（<50cfu/g）。未检测到肉毒梭菌毒素。在整个储存期间，在0-2℃的所有包装气氛中均未使还原亚硫酸盐梭菌繁殖。采用60%二氧化碳/40%氧气的气调包装可抑制气单胞菌属和肠杆菌科的生长，嗜冷菌、包括腐败希瓦氏菌在内的产硫化氢细菌、假单胞菌的生长最慢，并将微生物货架期延长至9-10天。本研究证实了在气调包装条件下储存的珍珠斑中，潜在致病性嗜水气单胞菌、维氏气单胞菌温和生物变种和维氏气单胞菌维氏生物变种在低温下能够生长存活。
