Nitrates and nitrites are used widely in the meat industry to cure. They are usually mixed with meat binders and cure ingredients and are added to dry sausages, semi-dry sausages, preserved meat and preserved meat by-products such as ham and salami. They can be added in the form of sodium and potassium salts (ex: sodium nitrate, sodium nitrite, potassium nitrate and potassium nitrite).
Nitrates and Nitrites
Nitrates and nitrites are used to:
Nitrates/nitrites control the growth of spores, particularly from Clostridium botulinum. These spores are a real concern in the food industry, because they can survive normal heat processing. Under the right conditions, they can produce vegetative cells, which can create a lethal toxin.
The use of nitrates or nitrites is restricted because high levels can be hazardous to humans. Excess nitrates can react with aminoacids in proteins during processing and form carcinogenic nitrosamines. Processors should have their systems checked during formulation to ensure the right levels are used.
Health Canada has identified maximum nitrites/nitrate levels in the Food and Drug Regulation, Division 16, Table XI (Table 1). These levels are well above those needed to stop the growth Clostridum botulinum spores.
Table 1. Maximum level of use for nitrites/nitrates
1 levels are calculated before smoking, cooking or fermentation
2parts per million (ppm) = mg/kg or mg/l
cured hams, loins and shoulder, poultry products
To comply with the regulations regarding the nitrate/nitrite levels in your products, you need to know the precise concentration of nitrates/nitrites in your recipes. Your supplier should be able to tell you what they are in your cure mix or meat binder. Use this information to calculate the amount of nitrates/nitrites in your formulation, based on your recipe.
For example, if your cure mix contains five per cent of nitrates and you use 36 grams in 10 kilograms of product, your product would have 179 parts per million.
The amount of nitrates you are adding is 0.05 x 36 grams = 1.8 grams
The product weight is 10.036 kilograms
There are 1,000 grams in a kilogram, so 36 grams = 0.036 kilograms.
0.036 kilograms + 10 kilograms = 10.036 kilograms of product
So, you will have 1.8 grams of nitrates in 10.036 kilograms of product.
To convert to parts per million (milligrams/kilograms)
There are 1,000 milligrams in a gram, so 1.8 grams =1800 milligrams.
1,800 milligrams/10.036 kilograms =179.4 milligrams/kilograms (parts per million)
NOTE: milligrams/kilograms can be expressed as parts per million, because one thousand milligrams = a kilogram.
You can also test your raw products for the total concentration of nitrates/nitrites at an external laboratory. To comply with the regulations, the sum of nitrates and nitrites should not exceed the maximum level (Table 1).
Hyytia, E., Eerola, S., Hielm, S., Korkeala, H., 1997. Sodium nitrite and potassium nitrate in control of nonproteolytic Clostridium botulinum outgrowth and toxigenesis in vacuum-packed cold-smoked rainbow trout. International Journal of Food Microbiology 37: 63-72.