As the season of fruits dawns on the state, food control officials are stepping up their vigil to ensure that mangoes and grapes are served in homes without chemicals dampening their taste and nutrition. Regional Analytical Laboratories are regularly testing samples collected from across Kerala as mangoes have started flooding the market. Last year, the Regional Analytical Laboratory had found that mangoes seized from vendors in the city are chemically contaminated as they used calcium carbide for ripening. The pesticide Benzene Hexa Chloride was also found to be present in samples of grapes.