For many, processed meats are a dietary staple. From the cold cuts in sandwiches and the pepperoni on pizza to the salami in charcuterie boards, these meats pose significant health risks. In 2015, the World Health Organization classified processed meats as a group one human carcinogen (Zhu, et al., 2014). The group one categorization is used when there is sufficient evidence of human carcinogenicity. The evaluation was used based on epidemiological studies that associated high consumption of processed meats with colorectal and human gastric cancer (Ward, et al., 2011).
The primary reason processed meats are implicated in the etiology of gastric cancer is due to the use of nitrates and nitrites as curing agents in the production of processed meat (Zhang, et al., 2023). While nitrates and nitrites are used for flavour and protection against lipid oxidation and bacteria spoilage in meat, they also form nitrosamines/ N-nitroso compounds (NOC) (Archer, 1989). These NOCs are carcinogenic because they form potent electrophilic alkylating agents in cells. These reactive intermediates are formed by spontaneous decomposition of nitrosoureas, alkylating agents that inhibit DNA repair, or by metabolic activation in the case of N-nitrosamines (Figure 1). Electrophiles like nitrosoureas subsequently react with the DNA of target tissues to form altered bases, leading to the initiation of carcinogenesis (Archer, 1989).
Figure 1. Graphical summary of how nitrates added to processed meats result in the formation of NOCs that can potentially cause DNA damage and form colon carcinomas (Crowe, Elliott and Green, 2019).
A study done by Chazelas, et al. (2022), showed increased risks of colon, kidney, and stomach cancer among people with higher ingestion of cured meats compared with low intakes (Chazelas, et al., 2022). The discovery of carcinogenic and genotoxic NOCs in processed meat products has significantly impacted the meat industry (Zhang et al., 2023). Residual levels of nitrites in cured meat samples have been constantly reduced and are in accordance with the legal limits set by most countries (Zhang, et al., 2023). In Canada, the maximum allowable concentration of nitrite salts that can be added to meats is 200 ppm; however, this varies based on the type of meat and the curing procedure (Government of Canada, 2018). To ensure consumer safety and compliance with regulatory standards, it becomes imperative for the meat industry to employ precise analytical methods for quantifying nitrites and nitrates in processed meats.
The primary analytical method for the determination of nitrate and nitrite in meat products is by anion exchange with ion chromatography, high-performance liquid chromatography, and ultraviolet (UV) absorbance detection (Siu and Henshall, 1998). This method allows for the analysis of commercial ham and salami samples using a chromatograph to determine the concentration of nitrate and nitrite (Figure 2). Since UV absorbance is specific for nitrate and nitrite, it eliminates interference from other ions present at much higher concentrations. Recoveries of nitrate and nitrite were found to be greater than 90%, highlighting the accuracy of the analytical method (Coviello, et al., 2020).
Figure 2. Chromatogram of nitrate and nitrite in salami extracts using an ion column with UV detection. The x-axis represents the time (minutes), and the y-axis is the signal corresponding to the response created by the detector, in UV absorbance units (AU). The negative peak eluting before the nitrite peak is due to chloride. The presence of this chloride peak was confirmed by suppressed conductivity detection in line with UV detection. The nitrite concentration is 9.85 mg/L, while nitrate is 10.8 mg/L, as highlighted by the different areas under the AU peak (adapted from Siu and Henshall, 1998).
Through the use of analytical methods, the meat industry can accurately quantify nitrites and nitrates in meats, allowing for optimization and control of these salt additives while also maintaining the desired qualities of the products. Monitoring these compounds in adherence to strict regulatory limits also allows for the safety of consumers. Nevertheless, although the meat industry is reducing its additive nitrite levels, it is essential to try and minimize the intake of cured meats to prevent the risk of gastric cancer and maintain overall health.
Works Cited
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Government of Canada, C.F.I.A., 2018. Preventive control recommendations on the use of nitrites in the curing of meat products. [fact sheet,reference material] Available at: <https://inspection.canada.ca/preventive-controls/meat/nitrites/eng/1522949763138/1522949763434> [Accessed 17 November 2023].
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Zhang, Y., Zhang, Y., Jia, J., Peng, H., Qian, Q., Pan, Z. and Liu, D., 2023. Nitrite and nitrate in meat processing: Functions and alternatives. Current Research in Food Science, 6, p.100470. https://doi.org/10.1016/j.crfs.2023.100470.
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