An official website of the United States government.
Field experiments will be used to examine the effect of plant variety, short-term fluctuations in light levels and time of day of harvest on the levels of nitrate in lettuce and spinach. <P>
The number of plants sampled, the mass of plants sampled and the sampling pattern will also be investigated to determine the optimum sampling plan for nitrate surveillance.
Nitrate is present in all vegetables naturally and also arises from the use of nitrogen fertilisers on crops. Vegetables, particularly green, leafy vegetables such as lettuce and spinach, contain the highest concentrations of nitrate and are a major source of nitrate in the diet. Although there are claims in the literature for deleterious effects of nitrate on consumer health, there are other studies that claim beneficial effects, especially when the nitrate is ingested as a component of vegetable matter rather than as an inorganic salt.
<p>
Since 1996, every Member State in the EU has been required to monitor and report on levels of nitrate in lettuce and spinach as part of a European Commission regulation which sets maximum levels. However, there is a high degree of variation in the results obtained by such sampling and while seasonal variation in crops and analytical methodology contribute to this variation, the sampling method used may also be a factor.
<p>
This project aims to investigate the potential sources of sampling variability for the analysis of nitrate in lettuce and spinach, and devise a recommended nitrate sampling plan for lettuce and spinach based on the results.
<p>
The conclusions for this project will be used to inform discussion on the European Commission Sampling Directive for nitrate in lettuce and spinach.
<p>Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food
Standards Agency Research webpage</a>.