The aflatoxin covenant includes an agreed sampling strategy. These agreements have been incorporated in a rule in the GMP scheme. The sampling strategy is based on the probability of contamination with aflatoxin. This probability is related to the size of the batch, the sort of animal feed and the country of origin. GMP-certified companies follow the following guidelines for the various sorts of raw materials:
- one sample per maximum of 500 tons if the raw material consists of peanuts, kapok and cotton seed, maize and maize by-products, palm kernels (from unknown origin) and by-products, rice products and safflower seed forage;
- one sample per maximum of 3,000 tons if the raw material consists of palm kernels (from Indonesia and Malaysia) or their by-products and sunflower seed forage.
In addition the Product Board Animal Feed examines materials from diverse countries: European and American maize and maize by-products, European rice products and Argentinean and European sunflower seed forage.
The results of the mixed feeds are clearly under the limit. Even the high 95 percentile level for mixed beef cattle fodder is under the strict limit for dairy cattle, of 5 µg aflatoxin per kg. In 1997 the median aflatoxin levels in feeds for beef cattle and pigs were 1.3 and 0.2 µg/kg respectively. No aflatoxin was found in mixed feed for poultry. The level of aflatoxin in raw materials for animal feeds has been well controlled since the aflatoxin covenant of November 1989.
Aflatoxin levels in raw materials of vegetable origin declined over the period 1989-1997. In 1997, 80 to 90 percent of the samples of maize, palm kernel, soy beans, citrus pulp and sunflower products contained no aflatoxin. Aflatoxin was commonly found in the sensitive peanut and coconut products. In 1997 the median in peanut products was 52 µg/kg, and in coconut products it was 13 µg/kg.
However these levels also exhibit a declining trend, and they remain clearly below the limit of 200 µg/kg. Batches of raw materials that exceed the limit of 200 µg/kg are taken out of the production process. In 1997 this happened only in the case of two batches of peanuts from Nigeria.
The presence of aflatoxin is to a large extent determined by the origin of the batch of raw material. Maize from Brazil and Argentina generally contains more aflatoxin than maize from North America. Only a little aflatoxin was found in palm kernel products from the most important exporting countries (Indonesia and Malaysia). Almost all peanuts imported come from Argentina and comply with the norm of 200 µg/kg. Higher levels are found incidentally in peanuts from Nigeria, Niger and the Sudan. Most coconut and coconut products from the Philippines and Indonesia easily comply with the residue limits for raw materials.
In 1997 many vegetable raw materials were checked for the undesirable element cadmium. The median levels and 95 percentile values for soybean husks, soybean forage, maize gluten feed, palm kernel husks and citrus pulp are well below the cadmium limit for unmixed feeds of 1 mg/kg. The median levels are less than 1 percent of the cadmium limit.
The cadmium levels in sunflower seed products and linseed are somewhat higher, but they are within the limit. The cadmium levels in most mineral mixes also comply with the norm. Elevated levels are found only incidentally in specific mineral products (such as zinc oxide and zinc sulphate). In general it can be said that cadmium is under good control.
Organochlorine compounds and PCBs
Organochlorine compounds and polychlorobiphenyls were found in a few samples of mixed feeds and unmixed raw materials. In the feed fats, one sample was found that exceeded the residue limit. In view of the sort of samples and their suspect origin, it can be concluded that the levels comply well with the animal feed regulation on residues.