Nitrogen is essential for all living things as it is a component of protein. Nitrogen exists in the environment in many forms and changes forms as it moves through the nitrogen cycle. Nitrates are natural constituents of plant material, and the effect of commercial nitrate-containing fertilizers on the nitrate content of vegetables is inconsistent. Because the intake of naturally occurring nitrates from foods such as green beans, carrots, squash, spinach, and beets can be as high as or higher than that from well water, these foods should be voluntarily monitored for nitrate content to ensure the quality of your product. Toxicology The reason for a preferably low intake is that ingested nitrates can be transformed into nitrites. Nitrites can affect the ability of the blood to transport oxygen, by transforming haemoglobin, the protein that carries oxygen in the blood into methaemoglobin, a form of the protein which is unable to carry oxygen. This is especially dangerous for infants up to 6 months. Furthermore nitrites are able to react with other components, such as secondary or tertiary amines and amides derived from food and from other sources, to form well recognized carcinogenic and mutagenic substances, at least to animals, called nitrosamines/amides.
The importance of knowing whether your food has safe levels of nitrate cannot be overemphasised. This is because nitrate poisoning has been proved to cause cancer and a blood disorder known as methemoglobinemia which inhibits oxygen distribution within the body.
We use high performance liquid chromatography (HPLC) and UV detection to test for nitrates and nitrites in food and feed. HPLC is basically a highly improved form of column chromatography. Instead of a solvent being allowed to drip through a column under gravity, it is forced through under high pressures of up to 400 atmospheres. That makes it much faster. It also allows us to use a very much smaller particle size with much better separation of the components of the mixture, achieving a much lower level of detection from a smaller initial sample size in a faster turnaround time.
Permitted levels of nitrate will depend on whether the product in question falls into the general (non-heat treated) meat product category (permitted up to 150 mg/kg) or into one of the traditional categories e.g. bacon/ham (permitted up to 250 mg/kg) or cured tongue (permitted up to 10 mg/kg). Permitted levels for spinach, lettuce and rucola are between 2000 and 7000 mg/kg depending on the time of harvest. Permitted level of nitrate for infant food is 200mg/kg. The acceptable daily dose of nitrate in food is currently set at 300 mg/day for an adult.
|Accredited Nitrate/Nitrate||Fish, Vegetables, Meats, Infant food, Infant formulae, Milk powder|
Current turnaround time: 10 working days from receipt of samples
Method used: High performance liquid chromatography (HPLC) and UV detection
Sample sized required: 100g
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