Feed and agriculture testing

Aflatoxin in feed does not stay in feed. In a dairy herd, aflatoxin B1 is metabolised and appears in the milk as aflatoxin M1 — so a finished-product failure at the dairy is often a purchasing decision at the feed mill, made weeks earlier. DON behaves differently: it rarely becomes a consumer-facing result, but it shows up as reduced intake and lost performance long before anyone thinks to test for it. The two toxins fail in different places, and a testing plan has to cover both.

For contaminant and toxin limits, the reference the Kingdom applies is SFDA.FD CAC 193. Where a feed-specific limit or a customer specification applies instead, the laboratory confirms the applicable limit in writing before testing — a mycotoxin number without its limit decides nothing.

An aflatoxin result on incoming grain protects every product the animal will ever make. The same result on the milk arrives after the loss.

A feed mill inherits the quality of what it accepts. Grain, oilseed meals and by-products arrive with a supplier declaration; the intake decision is whether to trust it. A verification programme does not test every load — it tests on a defined basis, holds material until the result that matters is in, and releases the rest on the supplier’s history. The laboratory’s part is a result that arrives inside the holding window and states plainly whether the material passes.

Cereal grains

Moisture at intake, mycotoxin screen before silo

Protein meals

Declared protein verified, Salmonella before release

Finished compound feed

Proximate check against the formulation

A feed label declares protein, fibre and moisture, and the buyer prices the bag on those numbers. A declared value that formulation software predicted but no laboratory ever confirmed is an exposure — to the customer who checks it, and to the mill when a complaint arrives. Periodic proximate testing of finished feed against its own declaration is how a mill knows its label is true. Where a declared tolerance applies, the laboratory confirms it in writing.

Crude protein

The value the price is built on

Moisture

Drives stability in storage — and paid weight

Crude fibre

Where formulation drift shows first

Feed is a recognised route for Salmonella into a livestock operation, and protein meals are the usual carrier. Surveillance of ingredients and finished feed finds the problem before it reaches a house or a herd; a clinical finding downstream finds it afterwards, at far greater cost. Salmonella detection at Nexus runs to a published international method, and whether it falls inside the SAAC-accredited scope is confirmed in writing with the quotation.

Feed criteria vary by ingredient, by customer and by destination market. Before a surveillance programme starts, the laboratory confirms the criteria it will report against in writing.

On the crop side, pesticide residues are the result a buyer asks for and a grower has to be able to show. The maximum residue limit depends on the crop-and-pesticide pair, so the laboratory confirms the applicable limit in writing before testing and reports the result against it. For livestock production, veterinary drug residues are governed by GSO 2481 — a separate limit set from pesticides, and often confused with it.

Water sits behind both sides of the operation — drinking water for livestock, irrigation water for crops. There is no single limit that covers every use, and pretending otherwise helps nobody. The parameters and criteria depend on what the water is for; the laboratory agrees them in writing before the first sample is drawn.