Arritt Fletcher M, Eifert Joseph D, Jahncke Michael L, Pierson Merle D, Williams Robert C
Department of Food Science and Technology, Virginia Tech, Duck Pond Drive, Blacksburg, Virginia 24061, USA.
J Food Prot. 2007 May;70(5):1159-64. doi: 10.4315/0362-028x-70.5.1159.
Packaging fishery products under vacuum atmosphere packaging (VAC) and modified atmosphere packaging (MAP) conditions can significantly extend the shelf life of raw, refrigerated fish products. There is considerable commercial interest in marketing VAC and MAP refrigerated (never frozen) raw fish fillets. The objective of this study was to determine if Clostridium botulinum toxin development precedes microbiological spoilage in raw, refrigerated flounder fillets. Aquacultured flounder (Paralichthys dentatus) individual fish fillets either were packed with a film having an oxygen transmission rate (OTR) of 3000 cm3 m(-2) 24 h(-1) at 22.8 degrees C or were vacuum packaged or packaged under 100% CO2 with a film having an OTR of 7.8 cm3 m(-2) 24 h(-1) at 21.1 degrees C and were stored at 4 and 10 degrees C. Samples were analyzed by aerobic plate count (APC) for spoilage and qualitatively for botulinum toxin with a mouse bioassay. The results demonstrate that flounder fillets (4 degrees C) packaged with a film having an OTR of 3,000 were microbiologically spoiled (APC, > 10(7) CFU/g) on day 15, but there was no toxin formation, even after 35 days of storage. However, at 10 degrees C, toxin production occurred (day 8), but it was after microbial spoilage and absolute sensory rejection (day 5). Vacuum-packaged fillets and 100% CO2 fillets (4 degrees C) packaged with a film having an OTR of 7.8 were toxic on days 20 and 25, respectively, with microbial spoilage (APC, >10(7) CFU/g) not occurring during the tested storage period (i.e., >35 days). At 10 degrees C, in vacuum-packaged flounder, toxin formation coincided with microbiological spoilage (days 8 to 9). In the 100% CO2-packaged fillets, toxin formation occurred on day 9, with microbial spoilage occurring on day 15. This study indicates that films with an OTR of 3,000 can be used for refrigerated fish fillets and still maintain the safety of the product.
在真空包装（VAC）和气调包装（MAP）条件下包装水产品，可显著延长生鲜冷藏鱼产品的保质期。在销售VAC和气调包装冷藏（从未冷冻）的生鱼片方面存在相当大的商业兴趣。本研究的目的是确定在生鲜冷藏比目鱼片中，肉毒梭菌毒素的产生是否先于微生物腐败。养殖的比目鱼（牙鲆）鱼片，要么用在22.8℃下氧气透过率（OTR）为3000 cm³ m⁻² 24 h⁻¹的薄膜包装，要么进行真空包装，要么在100%二氧化碳下用在21.1℃下OTR为7.8 cm³ m⁻² 24 h⁻¹的薄膜包装，并分别在4℃和10℃下储存。通过需氧平板计数（APC）分析样品的腐败情况，并通过小鼠生物测定法定性检测肉毒杆菌毒素。结果表明，用OTR为3000的薄膜包装的比目鱼片（4℃）在第15天出现微生物腐败（APC，>10⁷ CFU/g），但即使储存35天后也没有毒素形成。然而，在10℃时，毒素在第8天产生，但这是在微生物腐败和完全感官拒收（第5天）之后。真空包装鱼片和用OTR为7.8的薄膜包装的100%二氧化碳鱼片（4℃）分别在第20天和第25天有毒，在测试的储存期内（即>35天）未出现微生物腐败（APC，>10⁷ CFU/g）。在10℃时，真空包装的比目鱼片中，毒素形成与微生物腐败同时发生（第8至9天）。在100%二氧化碳包装的鱼片中，毒素在第9天形成，微生物腐败在第15天发生。本研究表明，OTR为3000的薄膜可用于冷藏鱼片，并且仍能保持产品的安全性。
