Spoilage of Pasteurized Crabmeat by a Nontoxigenic Psychrotrophic Anaerobic Sporeformer

Abstract

Microbial spoilage occurred in machine picked, pasteurized crabmeat of the Blue Crab that had been canned in Maryland in the fall of 1989 and later in 1990. Spoilage in 1989 was first detected after hurricane Hugo, although the relationship between the onset of spoilage and the hurricane, if any, is unclear. The sole spoilage organism was identified as a nontoxigenic psychrotrophic anaerobic sporeformer. The pattern of spoilage suggested a build-up of this organism in machine picking operations. Spoilage was noticeably absent from hand picked pasteurized crabmeat from the same plant. While the psychrotrophic anererobic sporeformer, in some respects, culturally resembles the psychrotroph Clostridium arcticum, the crabmeat spoilage organism may be an unrecognized species. Spores of the crabmeat isolate heated in neutral phosphate buffer gave a thermal resistance curve from survivor data characterized by a D185 (85°C) equal to 15.6 min and a z-value equal to 17.8°F (9.9°C). In crabmeat, D-values calculated from fractional survivor endpoint data gave a thermal resistance curve characterized by an extrapolated D185 equal to 35 min and a z-value equal to 11.6°F (6.5°C). From these data, a process equivalent to ▪ = = 31 was incapable of destroying even a reasonably low number of spores of the psychrotrophic anaerobe in pasteurized crabmeat.