Residue analysis for Agricultural Products

n agriculture, the term ‘residue’ is generally used to describe the small amounts of agricultural and veterinary chemicals, or their breakdown products, that remain in or on an agricultural product.

In the broader context of food safety, a substance can be defined as a ‘contaminant’ if it is an impurity which gives consumers health, safety or cleanliness concerns’. Contaminants include residues arising from the use of pesticides and veterinary medicines, heavy metals (e.g. mercury, cadmium, lead), naturally occurring chemicals such as mycotoxins (toxins produced by certain fungi) and microorganisms.

All of these may be present in food, either through natural circumstances or as a consequence of industrial or agricultural activities.

Chemicals that may be detected as residues include:

• Antibiotics used to control bacterial diseases in animals
• Anthelmintics used to control internal parasites in animals
• Fungicides used to control fungal diseases in plants and plant products
• Insecticides used to control insect pests in crops, protect stored grain and control external parasites on animals
• Herbicides used to control weeds in crops
• Fumigants used to protect grain and sterilise soil, sheds and bee hives

The international/national designs residue monitoring programs in consultation with industries. This includes consulting on the following:

• Sampling rates
• Selecting chemical–commodity combinations
• Designing and managing sampling procedures, including sample collection, identification and dispatch to laboratories
• Procuring appropriate analytical services and monitoring their proficiency
• Managing and analysing data
• Initiating and collating the sampling activities

CHEMRTL undertake chemical analyses itself; sampling facilities are also available on the request.

CHEMRTL conducts performance evaluation and proficiency testing to determine their competence in specific chemical analyses. Such proficiency testing underpins the activities and promotes a high level of confidence in analytical results.

• Extent and results of previous monitoring for the chemical–commodity combination
• Availability of suitable sampling and analytical methods
• International and domestic perceptions of the chemical–commodity combination.