It is therefore essential that the quality of animal feeds is carefully monitored.
Some animals form part of the human food chain.
Intensive rearing of cattle, pigs, sheep and poultry can cause hygiene problems and can also lead to the presence of undesirable residues such as hormones and antibiotics in meats, eggs and poultry. Checks for food poisoning organisms and residues in foods are imperative. Intensive farming methods have brought problems to the farming of cereal and vegetable crops too. Use of fertilisers can lead to high nitrate levels in water. Pesticides, herbicides and related substances are widely used in agriculture, aquaculture, buildings and domestic situations and their use can lead to residues of chemicals in the food and the environment.