[Nitrates in canned spinach. Effects of technological treatments]

During the last twenty years, the nitrate content of spinach has regularly increased along with the use of nitragenous fertilizers. A study made in the center of Britain (France) shows that along with this growing nitrate content, the quantity of raw harvested spinach has practically doubled in twenty years. But for the same quantity of raw harvested spinach, the yield of canned spinach has noticeably lowered. In a cannery trials made to lower the nitrate levels (preheating, blanching, renewing water blanching) led to a loss of about 45% of nitrate (on a dry matter basis). However nitrate levels stay about the same in one kg of raw spinach and in one kg of processed spinach coming from the same batch. The only answer seems to be able and come from better agricultural practices.