Nitrite intake varies by age group
Nitrite is formed in the body from food that contains nitrate, such as vegetables. It is also used as such in meat products to prevent the growth of bacteria that cause food poisoning.
The permitted uses and maximum amounts for nitrite are based on EU legislation on food additives. According to the legislation, a maximum of 150 milligrams of nitrite per kilogram may be added, primarily applying to meat products. The usual amount of nitrite used in Finland is 80 - 120 milligrams per kilogram.
“Nitrite in food mainly originates from additives. If you tend to eat a large amount of sausages, the nitrite intake may easily exceed the acceptable daily intake,” says Johanna Suomi, PhD, a Senior Researcher at the Risk Assessment Research Unit.
Nitrite intake is highest for the middle-aged. By retirement age, it is reduced to a level lower than the exposure of 25-year-old adults.
The average nitrite intake of Finnish men between the age of 25 and 74 is about 40 per cent greater than that of women in a similar age group.
Nitrite necessary as an additive
Nitrite is added to meat products in order to prevent the growth of bacteria that cause food poisoning, such as Clostridium botulinum in particular, and to preserve the red colour of meat. A product’s list of ingredients indicates whether nitrite has been added during production.
“If nitrite content was reduced from the current level, we would have to make hygiene requirements stricter and cold chain management more efficient,” says Suomi.
The amount of nitrite from raw vegetables and fruit that forms in the body is not a cause for concern. Incorrect preservation of cooked vegetables, such as spinach, could cause nitrate in the vegetable to change into nitrite even before the vegetable is eaten. In the worst-case scenario, this could result in intoxication.
Permitted nitrite intake calculated carefully
In 2013, Evira, the National Institute for Health and Welfare, and the National Nutrition Council issued recommendations on the use of sausages, frankfurters and meat cuts for children under school-age.
The recommendations are based on results obtained using a calculation model developed in Evira’s Risk Assessment Research Unit. The calculation model was used for specifying weekly portion sizes for various meat products where the nitrite exposure would be equivalent to the acceptable daily maximum intake, taking into account children’s sizes. However, besides nitrite content, the recommendations take into account the amount of salt and hard fat in sausages, and they are therefore slightly stricter than recommendations based on the amount of nitrite alone.
“Nitrite exposure was calculated by combining content data with the food consumption data of the age group being studied in a calculation programme that uses the Monte Carlo principle. Based on the material entered into the MCRA programme, it calculates probabilistic assessments on the extent of exposure and an assessment about uncertainty,” says Jukka Ranta, PhD, a Senior Researcher at Risk Assessment Research Unit.
The nitrite content of meat products was determined using a capillary electrophoresis laboratory method. It is a quick analysis method that requires only a little sample preparation. The method developed for nitrate and nitrite was able to separate the compounds in a little over five minutes.
The results of the study have been published in a peer-reviewed scientific publication:
Suomi, J., Ranta, J., Tuominen, P., Putkonen, T., Bäckman, C., Ovaskainen, M.-L. Suvi M. Virtanen, Savela, K . Quantitative risk assessment on the dietary exposure of Finnish children and adults to nitrite. Food Additives & Contaminants 2016: Part A, 33:1, 41 - 53.
The article is based on a risk assessment report Kvantitatiivinen riskinarviointi lasten ja aikuisten altistumisesta nitraatille ja nitriitille (description in English).
Johanna Suomi, Senior Researcher tel. +358 40 822 5629
Jukka Ranta, Senior Researcher tel. +358 40 489 3374, Monte Carlo calculation principle
Christina Bäckman, Researcher tel. +358 50 413 8167, laboratory method