CHALLENGE STUDIES WITH CLOSTRIDIUM-BOTULINUM TYPE-E IN A VALUE-ADDED SURIMI PRODUCT STORED UNDER A MODIFIED ATMOSPHERE

Challenge studies were carried out on raw, cooked, and sterilized suri mi nuggets, inoculated with 10(4) spores/g of C. botulinum type E spor es. All products were packaged in air and air with an Ageless SS oxyge n absorbent and stored at 4, 12 and 25C. Toxin was not detected in any raw product throughout storage (28 days). The absence of toxigenesis was attributed to the low pH (4.1-4.3) due mainly to the growth of lac tic acid bacteria (10(7)CFU/g). Toxin was also not detected in any coo ked product after 28 days. Product pH did not decrease as previously ( due to the absence of LAB), but counts of C. botulinum still decreased throughout storage. In sterile nuggets, C. botulinum counts increased to 10(6) cfu/g at both 12 and 25C, respectively, by 28 days. Lactic a cid bacteria and Bacillus spp, were not detected throughout the 28 day s storage period. Toxin was detected by days 28 and 14 at 12 and 25C, respectively, and toxigenesis preceded spoilage. The absence of toxin in cooked nuggets was attributed to the anti-botulinal role by Bacillu s species, the predominant spoilage bacteria in cooked nuggets.