Chemical hazards in foods can be of following categories:
Naturally Occurring Chemicals
These chemicals are derived from a variety of plants, animals or microorganisms. In most cases, they are found prior to or during harvest. Although many naturally occurring toxins are biological in origin, they are traditionally categorized as chemical hazards.
Some examples of foods containing naturally occurring chemical hazards:
- Nuts, Seafood: Certain varieties or species produce an allergic reaction in sensitive people.
- Corn: Certain molds that grow on corn can create toxins (e.g., aflatoxin).
- Certain fish species (tuna, mahi-mahi): Spoilage of certain species of fish can result in production of toxic levels of histamine and related compounds.
- Molluscan shellfish: Some microscopic organisms and plants upon which they feed can produce toxins such as domoic acid which affect people but not shellfish.
Unintentionally Added Chemicals
Chemicals can become part of a food without being intentionally added. These incidental chemicals might already be in a food ingredient when it is received. E.g. certain seafood may contain small but legal residues of approved antibiotics. Packaging materials that are in direct contact with ingredients or product can be a source of incidental chemicals, such as sanitizers or inks.
Most incidental chemicals have no effect on food safety, and others are only a concern if they are present in too high amount. Incidental chemicals also include accidental additions of prohibited substances such as poisons or insecticides that may not be allowed at any level.
Examples of incidental contaminants that may be chemical hazards in food are:
- Agricultural chemicals (e.g., pesticides, herbicides): Can be acutely toxic if present in food at high levels and may cause health risks with long-term exposure.
- Cleaning chemicals (e.g., acids, caustics): Can cause chemical burns if present in food at high levels.
- Maintenance chemicals (e.g., lubricants, paint): Chemicals that are not approved for food use and may be toxic.
Intentionally Added Chemicals
These are intentionally added to food at some point during food’s growth, production and distribution. They are safe when used at established safe levels but can be dangerous when those levels are exceeded.
Examples of food additives that may be chemical hazards if used improperly:
- Vitamin A (nutrient supplement): Can be toxic in high concentrations.
- Sulfiting agents (preservative): Can cause allergic-type reaction in sensitive people.
- FD&C Yellow No: 5 (Tartrazine): Can produce an allergic-type reaction in (food coloring) sensitive people.
- Sodium nitrite (preservative): Can be toxic in high concentrations.
Allergen is a molecule which is capable of initiating an abnormal immune response in the individuals who are sensitive towards them. Allergens are mostly proteinaceous in nature. Allergens in food can lead to dangerous reactions in sensitive people. E.g. Peanuts, Fish, Dairy products, Seasame seeds, Milk etc. can be allergens for some individuals.
Usually IgE (Immunoglobulin E) antibody is involved in allergic reaction due to food substances. Symptoms can range from skin rashes, slight itching of mouth to migraine headaches to anaphylactic shock and death. Type and severity of reaction is determined by:
- Dosage of allergens.
- Administration route.
- Genetic factors of an individual.
- Frequency of exposure to allergen.