Food Contaminants

When food is contaminated with harmful chemicals and micro-organisms it can cause illness if eaten. Food quality in relation to public safety is a primary concern that has led to the introduction of stringent legislation setting maximum levels of contaminants in foodstuffs, particularly heavy metals.

Types of contaminants

  • Aflatoxins
  • Heavy metals
  • DCD
  • Genetically engineered corn & soy
  • Phytoestrogens
  • Phthalates & Bisphenol-A
  • Contaminants in water used to reconstitute formula


Aflatoxins are toxins produced by a mould that grows in nuts, seeds, and legumes

Although aflatoxins are known to cause cancer in animals, they are allowed in low levels in nuts, seeds, and legumes because they are considered "unavoidable contaminants."

It is believed that occasionally eating small amounts of aflatoxin poses little risk over a lifetime. It is not practical to attempt to remove aflatoxin from food products in order to make them safer.

The mould that produces aflatoxin may be found in the following foods:

  • Peanuts and peanut butter
  • Tree nuts such as pecans
  • Corn
  • Wheat
  • Oil seeds such as cottonseed

To help minimize risk, the producers test foods that may contain aflatoxin. Peanuts and peanut butter are some of the most rigorously tested products because they frequently contain aflatoxins and are widely consumed.

Heavy Metals

The most notorious heavy metal contaminants are mercury, lead, and cadmium. They tend to be dangerous because they bioaccumulate in animal tissues over time. Heavy metal contamination usually originates from polluted water supplies. Fish are most susceptible to heavy metal contamination.

Driven by consumer demand and quality, many food agencies around the world have introduced directives that stipulate maximum allowable concentrations for heavy metals in foodstuffs.


Mercury enters our food supply through several sources; the first is from contaminated water supply inhabited by fish that are later consumed by humans. Mercury concentrations in fish significantly exceed the concentrations in the water. Meat can also contain mercury, after environmental pollution of fields that livestock use for grazing. Mercury is not commonly found in plant products, but it can enter human bodies through vegetables and other crops when sprays that contain mercury are applied in agriculture. Mercury exposure affects the central nervous system, brain functions, causes DNA and chromosomal damage, and causes reproductive problems. The most common route of human exposure to mercury is through environmental contamination of food sources.


Lead is one of four metals that have the most damaging effects on human health. It has a variety of applications - from use in pipes and paints, to its use in pesticides and a number of other applications. It can enter the human body through uptake of food (65%), water (20%) and air (15%). Many foodstuffs, including fruit, vegetables, meat, grains, seafood, soft drinks, and wine, contain lead. Cigarette smoke also contains small amounts of lead. Lead can enter (drinking) water through corrosion of pipes; this is more likely to happen when the water is slightly acidic - that is why public water treatment systems are now required to carry out pH-adjustments of drinking water. Lead causes many problems in the human body upon bioaccumulation such as disruption of blood synthesis, kidney damage, high blood pressure, miscarriage, low sperm count, etc.

Lead in water used to reconstitute formula can cause elevations in blood lead levels if used from the hot water tap or boiled. Boiling concentrates lead.


Human exposure to Cadmium is most always through food. It often shows up paired with zinc, and is a by-product of zinc, lead and copper extraction methods. Cadmium exposure is compounded in the body by consuming foods rich with this element, such as mushrooms and shellfish. Additionally, Cadmium is present in cigarette smoke, which acts as a blood transport mechanism for cadmium into the lungs. It can also travel via the blood into the liver and then into the kidneys.

Cadmium levels can be six times higher in soy formula compared to milk- based formula. Cadmium is also found in cereals with the exposure of dietary cadmium from weaning diets up to 12 times higher in children fed infant formula compared to breast milk.

Dicyandiamide (DCD)

DCD is the active compound used in some slow release fertilisers which are applied to grazed pastures to control nitrogen losses and promote pasture growth.

Currently there is no international standard for DCD, but residues have been detected in foods. Although it is not considered to have an impact on food safety, the presence of DCD residues in foods could be unacceptable to consumers both domestically and internationally and may present a trade risk.

Dairy products tested for DCD

Includes - butter, butter milk powder, caseinate, casein, lactoferrin, anhydrous milk fat (AMF), whey protein isolate, skim milk powder (SMP), whole milk powder (WMP), whey protein concentrate (WPC), liquid milk, milk protein concentrate (MPC), cheese, colostrum and nutritional products.

Genetically engineered corn and soy

Transgenic ingredients pose the risk of introducing novel toxins, new allergens, and increased antibiotic resistance in infants. The FDA does not require labeling of genetically engineered foods, so parents remain unaware that their baby is consuming transgenic ingredients MSG (processed free glutamic acid and processed free aspartic acid). These are known neurotoxins found in a number of infant formulas. Because the blood brain barrier is not fully developed in infants, these neurotoxins are more accessible to the infant brain than the adult brain.

The highest levels of these neurotoxins were found in hypoallergenic formulas. Because no studies have been done on the long term outcomes of infants fed on hypoallergenic formulas it is unknown if they will exhibit more learning disabilities at school age, and/or more endocrine disorders such as obesity, and reproductive disorders, later in life.


Phytoestrogens are endocrine disruptors found in soy formulas. Infants fed soy formula can have circulating phytoestrogen concentrations that are 13,000-22,000 times higher than normal levels in early life. These bioactive compounds can create steroid hormone imbalance, compete with enzymes that metabolize steroids, drugs and xenobiotics, and can influence gonadal function. Soy formula has been linked to premature thelarche (breast development in infants and girls under eight years of age). Phytoestrogens (isoflavones) also act on the thyroid gland. They are well known inducers of goiter and anti-thyroid agents. They act against the thyroid by inhibition of thyroid peroxidase. Children with autoimmune thyroid disease were three times more likely to have been fed soy formula in infancy.

Phthalates and Bisphenol-A

These are endocrine disrupting industrial chemicals. Phthalates are used as plasticisers and are testicular toxins as well as estradiol imitators.

Bisphenol-A is used in the production of polycarbonate plastics and has been found in plastic baby bottles. It can leach from the container and has been known to be estrogenic since 1938. Bisphenol-A resins are used as lacquers to coat metal products such as food cans. With a high affinity for fatty products, it has been shown to leach into the content of cans during the autoclaving process, including cans of milk-based infant formula.

Contaminants in water used to reconstitute concentrated and powdered formula


Infants fed formula reconstituted with nitrate-contaminated water are at risk for potentially fatal methemoglobinemia. Nitrates are converted to nitrites by the baby resulting in hemoglobin being converted to methemoglobin that cannot bind molecular oxygen. This risk increases if babies under six months are also fed baby food with high concentrations of nitrates such as green beans and bananas.


Atrazine is a weed killer that causes mammary and uterine cancer in rats. In the cities and towns with the worst tap water contamination, formula-fed babies who consume reconstituted formula would receive a lifetime dose of this chemical in the first four months of their lives.


Significant bacterial contamination can occur during home preparation of powdered infant formula. Reconstituted formula stored in the refrigerator shows increasing bacterial counts over time.