Review Examines Strategies for Reducing Nitrites, Nitrates in Processed Meats While Ensuring Microbial Safety
Reducing nitrite and nitrate concentrations in processed meats may be possible without compromising microbial safety, but their effectiveness depends on the pathogen and food matrix, according to a new review published in the International Journal of Food Microbiology. The authors concluded that hurdle approaches combining reduced nitrite and nitrate levels with other antimicrobial interventions represent the most promising strategy.
The review, authored by researchers from Teagasc Food Research Center and University College Dublin, examined strategies for reducing or replacing conventional nitrites and nitrates in processed meats while maintaining microbial safety. Nitrites and nitrates have traditionally been used for their antimicrobial effects, especially against Clostridium botulinum, as well as for their antioxidant activity and contributions to the characteristic color and flavor of cured meats.
However, concerns about the formation of carcinogenic N-nitrosamines have driven efforts to reduce the use of nitrites and nitrates. Commission Regulation (EU) 2023/2108 reduced maximum permitted levels for nitrites and nitrates in processed meats, effective October 2025.
Nitrite Alone Cannot be Assumed to Provide Total Microbial Safety
Available evidence suggested that lower concentrations of sodium nitrite could control some microbial hazards. For example, studies included in the review reported that 50–75 parts per million (ppm) of sodium nitrite inhibited C. botulinum toxigenesis under certain conditions, while 100 ppm was sufficient to ensure the microbial safety of minced roasted beef in one study.
However, Listeria monocytogenes showed greater tolerance to nitrite. One study found that 90 ppm of sodium nitrite significantly reduced, but did not completely prevent, L. monocytogenes growth in cooked ham, with growth observed at concentrations as high as 120 ppm. The authors therefore stressed that nitrite alone, at either current or reduced concentrations, cannot be assumed to provide comprehensive microbial safety across processed meat products.
For fermented meats, starter and protective cultures showed potential to supplement reduced nitrite and nitrate concentrations. Evidence supported the use of lactic acid bacteria and bacteriocin-producing cultures to control pathogens such as L. monocytogenes, Salmonella, and Clostridium spp. The researchers cautioned that product formulation, starter culture characteristics, and fermentation and ripening conditions must be considered when assessing safety.
Alternatives Include Plant Extracts, Organic Acids, HPP
The review also examined plant-derived ingredients, essential oils, phenolic compounds, organic acids and their salts, bacteriocins, and other antimicrobial substances as potential alternatives or complementary interventions.
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Although several plant-based ingredients demonstrated antimicrobial activity, the authors identified important limitations. Vegetable extracts used as natural sources of nitrite or nitrate do not eliminate concerns about N-nitrosamine formation. Such ingredients may also affect product color and flavor, introduce allergen concerns, and provide inconsistent antimicrobial activity because their composition can vary.
Nonthermal technologies, including cold plasma, high-pressure processing (HPP), and irradiation, also showed potential. For example, reviewed studies demonstrated that HPP could contribute to L. monocytogenes control in reduced- or nitrite-free meat products. However, bacterial spores are comparatively resistant to HPP, and pressure-resistant or sublethally injured cells may present additional food safety considerations.
Hurdle Technology Identified as Most Promising Approach
Overall, the researchers concluded that no single alternative currently fulfills all of the antimicrobial and technological functions provided by conventional nitrites and nitrates. Instead, they identified hurdle technology as the most promising approach, combining nitrite and nitrate concentrations of 75–100 ppm with alternative antimicrobial compounds, starter or protective cultures, and/or nonthermal processing technologies, depending on the product.
The authors called for additional research to validate product- and pathogen-specific hurdle strategies, particularly against C. botulinum, Clostridioides difficile, L. monocytogenes, and Salmonella. Studies should evaluate interventions under both recommended and temperature-abuse storage conditions, while also considering sensory quality and consumer acceptance.
