D CONTROL (pasteurized fish products)

D CONTROL (pasteurized fish products)

Summary

Significant hazards a r Aquatic toxins. r Histamine.

r Cl. botulinum . r L. monocytogenes (if handled after heating). r Human enteric pathogens (if handled after heating).

Control measures

Initial level (H 0 )

r Avoid fish from algal blooms. r Avoid fish from specific (tropical) areas.

Reduction (Σ R)

r Time × –temperature during heating.

Increase (Σ I)

r Time × –temperature during storage. r GHP to prevent cross-contamination.

Testing

r L. monocytogenes (if no knowledge of prior history).

Spoilage

r Time × −temperature. r Sensory evaluation

a Under particular circumstances, other hazards may need to be considered.

Hazards to be considered. Both aquatic toxins and biogenic amines are hazards in these types of products and if formed in the raw material are not removed by the heating step. Vegetative bacterial cells are typically killed by the pasteurization process but spores may survive and Clostridium botulinum is a major hazard in these products if vacuum-packaged. Post-process contamintion with L. monocytogenes can occur and constitutes a health hazard in vacuum-packed, chill-stored products such as hot-smoked fish.

Control measures Intial level of hazard (H 0 ). As described under fresh finfish, aquatic toxins should be controlled

by surveillance of catching waters thus controlling H 0 . Avoiding problems with Cl. botulinum in hot- smoked products requires action at all levels of the process. Frequent and effective clean up will keep

ambient contamination by Cl. botulinum at low levels (H 0 ).

C during the process greatly reduces the chances for survival and subsequent growth of Cl. botulinum serotype E (Eklund et al ., 1982a; Pelroy et al., 1982). The temperatures used in hot smoking and sous-vide treatment are sufficient to kill L. monocytogenes (Ben Embarek and Huss, 1993).

Reduction of hazard (Σ R). Heating to an internal temperature in excess of 82 ◦

Increase of hazard (Σ I). Biogenic amines are controlled by keeping raw materials chilled (≤2 ◦ ) avoiding growth of decarboxylating bacteria (controlling ΣI). Clostridium botulinum control also re- quires barriers against growth. Control of formulations, particularly salt and nitrite levels, and of tem- perature is essential to prevent growth (ΣI). As for lightly preserved products, a water phase salt level of 3.5% combined with storage at temperatures at or below 5 ◦

C will prevent growth and toxin production for at least 4 weeks. Since the temperatures used are sufficient to kill L. monocytogenes,

235 proper cleaning and sanitation of the proces environment is crucial to avoid post-process contamina-

FISH AND FISH PRODUCTS

tion (ΣI). Testing. Measurements of NaCl percentage and temperature are important to document control of

psychrotrophic Cl. botulinum. Plant contamination with L. monocytogenes must be evaluated and if the organism is present, testing of finished product can determine if a food safety objective (e.g. 100 L. monocytogenes per gram at consumption) can be met.

Spoilage. Ensuring appropriate heating steps and, if required, subsequent chill storage are control measures to limit microbial spoilage. No specific testings are recommended for this purpose.

XIII Canned seafood

A Processing Canned seafood products such as salmon, tuna, and sardines, which are given a full retort process,

should be “commercially sterile” and free from living bacteria that are potentially pathogenic. For such foods, the bacteriological hazards are the same as those for other low-acid canned foods and relate, with one exception, to problems of improper or inadequate processing or leakage. Adequate process control is the key to ensure a safe final product.

The one exception relates to scombroid poisoning. The toxin responsible (see above) is resistant to heat, and cases of scombroid poisoning have resulted from consumption of canned tuna (MMWR,1975). Although scombroid poisoning from canned tuna and bonito is mainly due to the development of histamine in the fish prior to processing, the condition may be exacerbated by increased histidine decarboxylase activity during processing. Significant increases in histamine levels were observed ex- perimentally after bonito was processed at 116 ◦

6.0 (Pan and James, 1985). However, excess histamine in fish destined for canning does not appear to be a significant problem (Lopez-Sabater et al., 1994).

C to an F 0 =