Testing for adulteration

The current crisis of melamine adulterated milk powder in China raises some interesting questions. How should quality assurance personnel determine what tests they need to perform to ensure the integrity of a product?

It is usual practice to ensure that incoming and finished goods are tested to ensure they meet their specifications. Sampling, test and calibration procedures and result tolerances are established and the actual testing becomes a routine part of the laboratory activity. Whenever the results are outside the established range, alarm bells ring and corrective action implemented.

Each product is defined by its specification — if it meets the spec it is suitable for use or dispatch. But what happens if the product is adulterated, if it meets its spec but isn’t what it is supposed to be?

The world at large is currently asking why wasn’t the milk in China tested for the presence of melamine? This sort of question implies that all products should be tested for absolutely everything — a patently ridiculous assertion.

In fairness, why would anyone have tested milk for melamine? Until the pet food scare last year in the US, Europe and South Africa where dogs across those countries were dying of kidney failure, melamine was not even on the radar screen for food ingredient testers.

Possibly a more pertinent question would have been why the crude protein levels in the milk were routinely out of kilter with the fat levels. This is the sort of information you could reasonably expect a laboratory to collate.

However, with widespread, regular, long-term adulteration as appears to have been the case in the Chinese milk/melamine scandal, questions should have been coming from management and government.

Adulteration on a large scale is by its very nature known to many. Melamine producers must have been aware that they were delivering product to an unlikely location. Someone was placing the purchase orders and lots of people had to have known what was going on. If the knowledge wasn’t well known, there could not have been as many different people doing the same thing.

This sort of knowledge does not automatically filter through to laboratory personnel even when it is well known within management. Responsible managers and government inspectors and regulators should and would have known what was happening. This information should have been made available to the laboratories so that suitable test procedures could be implemented.

Saying that the people involved assumed melamine is harmless and so the adulteration was just good business is not acceptable. Even management and government are aware that milk is one of the basic foods and that substituting protein with a nitrogen-rich non-nutrient is unsupportable.

The responsibility for uncovering the adulteration should not be considered to be primarily a laboratory function. Good management and leadership are essential.

So the question remains — how does the laboratory decide what tests will ensure the correct results are ascertained?