Food contamination refers to the presence in food of harmful chemicals and microorganisms which can cause consumer illness. In food analysis the term contaminant is often used to refer to chemical contamination, whereas microbiological contamination is identified separately.
Chemical contaminants are often persistent in foods, surviving the various processing stages used in manufacture. Their effect on consumers is often seen only after many years of prolonged exposure at low levels, causing cancers or toxicological and metabolic problems.
The Commonest Types of Chemical Contaminants Are:
- Agrochemicals. Chemicals used in agriculture and farming to eliminate pest and disease, improve yields, or reduce costs. These include various types of pesticide, veterinary drugs used in animal husbandry and aquaculture, fumigants and plant growth regulators.
- Environmental contaminants from air (polycyclic aromatic hydrocarbons- PAH); water (metals, solvents), soil (metals, nitrate and nitrites)
- General contaminants such as polychlorinated biphenyls (PCBs), dioxins, etc.
- Contaminants from packaging materials; bisphenol A, metals, solvents and plasticisers
- Processing contaminants from equipment, copper and other metals, lubricants, cleaning agents, etc.
- Naturally occurring contaminants, often as a secondary feature of microbial or mould spoilage- mycotoxins, phytohaemagglutinin, scombrotoxin etc.
- Materials that are fraudulently added to reduce costs of food materials, for example melamine, leather hydrolysates, undeclared additives.
- Illegal dyes and colours, Sudan dyes etc.