Illegal Nitrite Treatment of Red Tuna and Prolonged Storage: What About Other Food Safety Risks?

The illegal treatment of tuna with nitrite is a significant food safety concern. The risk may be due to not only the high nitrite levels and the possible formation of N-Nitrosamines but also to the possible increase in biogenic amines and microbial load and also pathogens. This study optimized the treatment of red tuna (Thunnus thynnus) with nitrite solutions and then determined several chemical (histamine, total volatile basic nitrogen (TVBN), biogenic amines, nitrite/nitrate, ascorbic acid, and sulfites) and microbiological (total microbial count, Enterobacteriaceae, Vibrionaceae, coagulase-positive staphylococci, Salmonella, Escherichia coli) parameters, comparing the results obtained with fresh samples with those obtained with treated samples after 5 days of storage (4 °C). The effect of such treatment on samples voluntarily contaminated with some pathogens was also investigated. The results indicate that if the products are characterized by suitable hygienic quality, the total microbial load and the levels of histamine and TVBN after 5 days of storage are below the legal limits, and no health risk subsists. The growth of pathogens/histaminogens (Salmonella and Morganella morganii) was also substantially inhibited during storage. Thus, this work confirmed that the high nitrite amounts and the possible development of N-nitrosamines represent the only significant food safety concerns.