Nitrite, and in some cases nitrate, are functional food ingredients that serve as effective antimicrobials to inhibit pathogens such as Clostridium botulinum and Listeria monocytogenes, impart a distinctive cured color to meat products, provide antioxidant properties to retard lipid oxidation and extend the shelf-life of these traditional products. Some concern has been raised about the use of these ingredients and whether their level of use truly poses a sufficient health risk to warrant their restriction or removal from cured meats. Because approximately 12 years have passed since a survey of cured meat products has taken place in the U.S., we conducted a comprehensive survey to document the actual levels of nitrite/ nitrate (NO2/NO3) in cured meats and raw vegetables offered at retail. This would establish a comprehensive database for comparison to other historic surveys and in turn, validate the limited contribution of cured meat products to the total dietary nitrite/ nitrate load.
A random survey of 467 cured meat products representing 6 major categories and 197 fresh, raw broccoli, cabbage, celery, lettuce and spinach samples were taken from retail outlets in 5 U.S. cities (Chicago, Dallas, Los Angeles, New York, Raleigh). This survey is the first to our knowledge to evaluate the NO2/NO3 content of organic meat and vegetable product categories. NO2/NO3 concentrations in drinking water of 25 major U.S. cities were also compiled to provide an additional database for evaluating water’s contribution to NO2/NO3 load.
In general, there were no differences in nitrite levels between conventional and organic cured meat categories nor across the cities surveyed, but a few organic products surveyed in certain cities were lower in nitrate content. NO2/NO3 levels averaged 0.64/ 35.66, 0.74/ 78.81, 1.95/ 67.43, 6.86/ 27.68, 7.16/ 14.81 and 7.31/ 25.57 ppm, respectively, for fermented cooked sausage, cured dried uncooked sausage, whole-muscle dry-cured cooked, cured cooked sausage, whole-muscle brine cured cooked and whole-muscle brine cured uncooked categories. Weighted means for NO2/NO3 across all cured meat categories were 4.54 and 37.07 ppm, respectively. Thus, nitrite values observed were not appreciably different from those previously reported by Cassens 12 years ago and were substantially lower than those reported by National Academy of Sciences (1981) as well as those from other countries.
Very few differences were noted in nitrite levels of conventional and organic vegetables, but the nitrate content of organic vegetables were lower. Nitrate levels of conventional broccoli, cabbage, celery, lettuce and spinach were 394.38, 417.56, 1,495.48, 850.46 and 2,797.18 ppm, respectively, while their organic counterparts averaged 204.29, 551.97, 911.94, 844.06 and 1,317.73 ppm. The fact that the nitrate contents of vegetables are variable poses a potential dilemma for determining their actual nitrate contribution to the diet. Based on this survey, regional variation may need to be taken into consideration when developing nitrate consumption predictions based on specific vegetables. This variation might be of sufficient magnitude to alter epidemiological predictions if not considered appropriately. All drinking water sources were within the allowable limits for nitrate (and nitrite if reported) established by the EPA.
Overall, nitrite/ nitrate contents of U.S. cured meat products have remained low since the last national survey in 1997. It appears that the current USDA regulations and manufacturer’s processing procedures are consistently controlling the levels of nitrite/ nitrate in cured meat products and continue to be effective for minimizing their contribution to the dietary nitrite/ nitrate load.
Dr. Jimmy T. Keeton
Department of Nutrition and Food Science
Texas A&M University
College Station, TX 77843-2253