A 1999 study conducted by the All India Co-ordinated Research Project on Pesticides Residue (AICRP) on vegetables and fruits confirmed this, when it found 90 to 100 per cent samples from 4 states and 45 to 80 per cent samples from 12 states to be contaminated with pesticides.
Another 2003 research funded by U.K.'s Department for International Development found 72 per cent palak samples from Delhi contained lead and 21 per cent contained zinc that exceeded the limits set by the Prevention of Food Adulteration Act (PFA).
These metals were also found in many of the 69 brands of chocolates and candies tested in Mumbai. Applying the internationally recognised Polish standards that limit lead in chocolates at 0.30 mg/kg and cadmium at 0.05 mg/kg, 42 chocolates had excess lead and 19 excess cadmium.
Incidentally the same toxic metals and silver showed up in edible foil used to wrap sweets and betel nut products.
But these aren't the only contaminants we need to worry about. Between 1998 and 2000 several consignments of Indian chillies and nutmeg were rejected internationally due to presence of aflatoxins, a natural poison produced by moulds due to improper drying.
Botulism, caused by the Clostridium bacteria, found in improperly canned low-acid foods, such as green beans, mushrooms, spinach, olives, beef and fish , causes respiratory paralysis. E. Coli reported in dairy products such as milk, yoghurt, soft cheeses & even in weaning foods is a leading cause of kidney failure in children. And Salmonella enteritidis carried by chickens causes gastro-enteritis.
While commonly used food colours like lead chromate, dyes like metanil yellow, Rhodamine B and Sudan I can cause abnormalities and mental retardation, flavour enhancer 635 found in Nestlé's 2-minute Maggi noodles has caused severe itching and skin disruptions in many.
Non-vegetarians are doubly vulnerable, having to deal with residues of antibiotics like penicillin and growth hormones such as estradiol , progestins and testosterone in their meat. While the residues of the former can cause anaphylactic reactions, concentrations of the latter cause hormonally mediated diseases like breast and prostate cancer . Supermarkets internationally have now started stocking marginally expensive antibiotic-free meat and poultry.
Added to these, a recent study by Leatherhead Food International found that wrappers and packaging used for foods contain hidden quantities of latex rubber, which can trigger fatal allergic reactions. They found one chocolate biscuit which actually had 17 ng/ml of latex inside it, transferred to it from the wrapper.