Predicting the Safe Storage of Fresh Fish Under Modified Atmospheres with Respect to Clostridium botulinum Toxigenesis by Modeling Length of the Lag Phase of Growth

Abstract

The toxigenesis of non-proteolytic C. botulinum, types B, E, and F, in a variety of fresh fish stored between 4 and 30°C for up to 60 days was evaluated in a five year study. Muscle homogenates and fillets were inoculated with 10⁴-10⁻² spores from multiple strain pools, then modified atmosphere (MA) packaged under vacuum, 100% CO₂, or 70% CO² and 30% N₂. Our conclusions are based on all data generated in 927 experiments comprising 18,700 samples. The earliest lag times (LT), i.e. sampling period prior to observation of toxicity, among all experiments conducted at 30, 20, 16, 12, 8, and 4°C, were 0.5, 1, 2, 3, 3, and 18 d, respectively. The LT across experiments was significantly affected by temperature (p2=0.883). The spore inoculum level accounted for 7.4%, while other factors explained C. botulinum toxicity in inoculated fish stored under different MA's, reported in the international literature.