Nitrite and nitrate levels in vegetables are a matter of concern due to their toxicity at high levels and nitrate high accumulation. Moreover, there is a lack of knowledge about their levels in some types of widely consumed vegetables such as chard and rocket. In this study, 124 Swiss chard and wild rocket samples were analyzed for determining nitrite and nitrate using validated and accredited analytical methods by ion chromatography with conductivity detection. High nitrite concentrations, up to 219.5 mg kg⁻¹ f.w., were detected in one Swiss chard and three wild rocket samples. One Margin of Safety (MoS) value was <1. Regarding nitrate, in Swiss chard samples the mean concentration (2522.6 mg kg⁻¹) was slightly higher than those reported in the literature for spinach and lettuce. No MoS was <1, but 83% of values were <100. Nitrate concentrations higher than the legal limit were quantified in 11 rucola samples. The verification of 25% of wild rocket samples with nitrate concentration higher than the legal limit confirmed the need for official control. This study also suggests the introduction of legal limits for nitrite/nitrate in Swiss chard and nitrite in wild rocket.

Nitrite and nitrate are well-known food additives used in cured meats and linked to different food safety concerns. However, no study about the possible effect of cooking treatment on the residual level of these compounds before consumption is available. In this work, 60 samples of meat products were analyzed in order to evaluate the variation in residual nitrite and nitrate level after baking, grilling and boiling. The analyses by ion chromatography demonstrated that meat cooking leads to a decrease in nitrite and an increase in nitrate residual levels in the final products. Meat boiling caused an overall decrease in two additives’ concentration, while baking and particularly grilling caused an increase in nitrate and, in some cases, nitrite as well. Some regulatory aspects were also considered, such as the possibility of revising the legal limit of nitrate from the actual 150 mg kg⁻¹ to a more cautious 100 mg kg⁻¹. Indeed, several meat samples (bacon and swine fresh sausage) resulted in a higher nitrate concentration than the legal limit after cooking by grilling (eleven samples) or baking (five samples). Finally, the Margin of Safety evaluation demonstrated a good level of food safety, all values being higher than the protective threshold of 100.

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.