Effect of the Gas Permeability of Plastic Film on the Growth of Anaerobes in Film-packaged Foods

Abstract

Studies were conducted on two kinds of anaerobes, namely Clostridium sporogenes and Clostridium perfringens, to determine what influence oxygen would have on the growth of these microorganisms in culture media and in fish sausages packaged in plastic casings having different oxygen gas transmission rates.
In thioglycollate media which were packaged in casings completely impermeable to oxygen gas, the growth of anaerobes was accelerated. When common types of casings which are supposed to have low oxygen gas transmission rates (70-170cc/m²/24 h, at 23°C) were used, no difference in growth was observed. The results implied that these ordinary types of casings could not maintain so high a degree of anaerobic condition as to accelerate the growth of anaerobes.
In fish sausages, different patterns of growth behavior were observed for anaerobes when they were coexistent with facultative anerobes.
Where the Dumber of facultative anaerobes was more than or equal to that of anaerobes, the former grew predominantly, even with no growth of the latter in some cases. As the ratio of the anaerobes became higher, their growth became more active.
It has been concluded that fish sausages in which anaerobes exist alone have some possibilities of being spoilt by the anaerobes even if they are packaged in casings having low oxygen gas transmission rates.