Toxic effects of food preservatives

Preservatives are chemical compounds that have fungistatic, bacteriostatic, antimicrobicidal or antioxidant properties. They are added to raw, processed foods like vegetables, fruit juices, confectioneries, bakery products, poultry, fish and meat products to inhibit souring, spoilage or growth of contaminants like bacteria, fungi, yeasts or molds. They are essential to prevent certain physicochemical changes in food such as browning, rancidity and also to maintain determined shelf life of the product. Preservatives also reduce destruction of amino acids and vitamins present in the food upto some extent.

The use of sodium chloride or common salt for food preservation or salting is the oldest food preservation method. Reduction in water or moisture content and hence retardation of fungal or bacterial growth is the principle behind the food preservation by salting. Organic acids like EDTA (Ethylene diamine tetracetate) acetic (vinegar), sorbic (ascorbic), benzoic, malic, propionic, citric and tartaric are routinely used as preservatives in households and food industries. They are used in pickles, salads, dressings and confectioneries to prevent discoloration, flavor change and rancidity. Organic acids lower the pH of food material and therefore retard bacterial growth. They act as chelating agents by scavenging metal ions like iron and hence prevent oxidation process maintaining the nutritional status of food. Ascorbic, propionic and citric acid are also used as antioxidants and antimicrobial agents.

Principle side effects of organic acids are headache, acidity, increase in blood pressure, dermatological reactions, asthmatic reaction and they are also carcinogenic. Sorbic acid and benzoic acid at high concentration were found to induce genotoxic and mutagenic effects in experimental mice; so their harmful effects on human system are likely evident. Sulphite group of chemicals are very common for preservation of margarine, cheese, whey, beverages, soups, sweets, meat and sea products. Sodium, calcium or potassium sulphites used in the preservation are known to trigger asthma, anaphylactic and allergic reactions. They may cause stomach ache, hives and breathing troubles. Nitrates of sodium and potassium are very important class of food preservatives. They are the only chemicals which inhibit the growth and sporulation of Clostridium botulinum, a causative agent of food poisoning botulism. Botulism is deadly fatal infection as compared to the side effects of nitrites. The bad effects of nitrites such as triggering of asthma, headache, severe dermatological reactions and their carcinogenic combination with amines and amides of foods are hence ignored. Butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA) and propyl gallate are added as antioxidants; they prevent oxidation of lipid components in food and rancidity. These antioxidants actually enhance the toxicity, mutagenicity or carcinogenicity of some compounds like poly-hydroxy alkonates (PHA). Antioxidant chemicals also cause liver tumors and stomach ulcers. Recently, application of microbin and monosodium glutamate (MSG) have increased with increase in popularity of Chinese food and ingredients such as noodles, soya, chilli, tomato and other sauces and soups. Both the chemicals act as flavor enhancers and preservatives in these foods. We ignore the warning 'MSG not recommended for children' written on noodle or soup packets since we are not aware of their ill effects or we don't want to stop eating our favorite cuisine. Microbin is a sodium salt of p-chlorobenzoic acid or methyl, ethyl or propyl ester of p-oxybenzoic acid. It causes glucosuria, albuminuria and renal dysfunction. MSG is responsible for obesity in children and adults; it also induces uncomfortable tingling sensation, headache and asthma. So give second thought before eating packed, stored or readymade food.

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