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Studies involving packaged fresh fish have shown that obvious spoilage can be delayed by removing oxygen.  However, anaerobic pathogenic Clostridium botulinum may thrive in such reduced oxygen packaging, causing packaged fish to become toxic prior to obvious spoilage.  In an attempt to mitigate development of reduced oxygen atmospheres within fresh seafood packaging, FDA has specified a minimum oxygen transmission rate (OTR) for seafood packaging films of 10,000 cc O₂/m²/day.  However, this specification does not take the actual package design into consideration.  It is suspected that a specification that combines film OTR with descriptive parameters of the package, such as film area, may offer a better structure for the specification.  Additionally, while it is generally accepted that C. botulinum is an obligate anaerobe, it remains unclear if a particular concentration of oxygen is capable of preventing toxigenesis. 

The objective of this work was to develop a scientific rationale for a new seafood package OTR specification, and to study the sensitivity of Clostridium sporogenes spore outgrowth to oxygen in plastic film packages.

OTR of four commercially available films were measured in ranges of 10-35˚C and 0-50% RH.  Different sized packages were made from these films. Petri dishes inoculated with C. sporogenes spores were placed in these bags, vacuum/gas flushed, sealed and incubated at 5, 10, 15, 25, 40˚C. Time required to spot visible colonies was recorded.

Measured OTR values demonstrated Arrhenius temperature sensitivity.  Additionally, package design parameters, such as film area and permeability appear to influence outgrowth of C. sporogenes spores.

Results suggest that package design and geometry should be incorporated in the permeability specification for reduced oxygen packaged fresh seafood.