🍲 Chemical Hazards in Food

This lesson builds core elective concepts in BSc Agriculture with practical applications and exam-oriented clarity.

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Chemical Hazards in Food

Chemical hazards in food originate from agricultural inputs, environmental pollutants, natural toxins, and substances introduced during processing. Unlike microbial hazards that typically cause acute illness, chemical contaminants often produce chronic health effects including cancer, organ damage, and endocrine disruption following prolonged low-level exposure.

Pesticide Residues

Pesticides are essential for crop protection, but their residues in food pose significant health risks when they exceed safe limits. Organophosphates and organochlorines can accumulate in food commodities and affect the nervous system. India regulates pesticide residues through the Maximum Residue Limit (MRL) system, which specifies the highest legally permissible concentration of a pesticide residue in or on a food commodity. MRLs are established based on Good Agricultural Practice data and toxicological evaluations, ensuring that normal dietary exposure remains well below harmful levels.

Heavy Metals

Lead, cadmium, mercury, and arsenic enter the food chain through contaminated soil, irrigation water, industrial emissions, and food contact materials. Lead exposure impairs neurological development in children, while cadmium accumulates in the kidneys and causes renal damage. Rice grown in arsenic-contaminated groundwater regions of West Bengal and Bangladesh is a well-documented concern.

Mycotoxins

Aflatoxins, produced primarily by Aspergillus flavus and A. parasiticus, are among the most potent naturally occurring carcinogens. They contaminate groundnuts, maize, tree nuts, and spices, particularly under warm and humid storage conditions. Aflatoxin B1 is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). Other significant mycotoxins include ochratoxin A, fumonisins, and deoxynivalenol.

Food Additives and Processing Contaminants

While approved food additives are generally safe within prescribed limits, unauthorized use of colours, preservatives, or adulterants remains a concern. Processing contaminants such as acrylamide (formed during high-temperature cooking of starchy foods) and polycyclic aromatic hydrocarbons (from smoking and grilling) also warrant monitoring and control.

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Summary Cheat Sheet

Topic	Key takeaway
Main focus	Chemical Hazards in Food.
Section context	Revise this lesson with the rest of Food Safety and Standards for stronger conceptual continuity.