Botulism Risk of Refrigerated, Processed Foods of Extended Durability

Abstract

Control of the botulism risk in refrigerated, processed foods with extended durability (REPFED) which do not contain intrinsic safety factor(s) has been analyzed. There are insufficient data on the heat resistance of spores of nonproteolytic Clostridium botulinum types B, E, and F, to ensure that the heating process used in preparation of REPFEDs provides adequate lethality. During portioning of foods and filling of trays, products may be exposed to recontamination if this process is not carried out under aseptic conditions. Pasteurization of sealed trays at a temperature of about 75°C for several minutes is a process which spores of C. botulinum can easily survive. For these reasons, REPFEDs must be stored at a temperature < 3.3°C, since such low storage temperatures prevent growth and formation of toxin by C. botulinum. At 8°C, a temperature to which chilled foods are often exposed during and after retail sale, nonproteolytic strains of C. botulinum can produce toxin within 3 weeks. In addition prestorage at 3°C for up to 2–4 weeks stimulates the toxinogenesis of nonproteolytic C. botulinum type B at a subsequent storage at 8°C. Heating of REPFEDs before consumption was not always sufficient to inactivate botulinum toxin completely. In order to ensure that the risk of botulism from these foods is controlled adequately, REPFEDs must be stored at a temperature < 3.3°C. If, however, this temperature cannot be guaranteed, the storage time has to be limited.