On Contaminant Scares and Canned Pineapples

Understaffing was a problem - the laboratories of the Department of Health, for instance, had a total of five analysts, compared to scores of analysts for one laboratory company in Britain.

24/08/07 Almost weekly, there are new health or contaminant scares in the food industry. Toxicologist Prof Mike Stewart, who currently works for SA's Department of Health, recently addressed a meeting of the SA Assoc for Food Science and Technology (SAAFoST) on "Food contaminants, what we should be measuring, how and why".

A major part of his address pointed out that there are valid and credible contaminant scares - for instance aflatoxin is a very serious contaminant.

However, they are many less credible ones, for instance:
* "Aluminium pots cause Alkzheimers disease" - which has been completely disproved.
* "Acrylamide causes cancer in humans" - which has nowhere been shown, although the incidence of tumour among rats in laboratory trials has been higher.
* Likewise for Sudan Red, no human cancer case has been attributable to it.
* Cadmium (at the centre of the recent SA canned pineapple debacle) - "in order to get the same amount of cadmium from pineapples as from one cigarette, one would need to eat 4kg of pineapples ... Yet the pineapple industry was decimated in SA because someone measured cadmium."

The problem, he said, traces back to imported zinc sulphate being used as a fertilizer, which always occurs with cadmium.

On the question of why then the permitted limits for these so-called contaminants are set so low in government regulations, he said that this was apparently because:

* They can be detected as that these low levels with modern equipment
* Different regulatory agencies agencies copy each other.
* Of vested interests - for instance, laboratories do many more tests with stricter permitted limits.

He said that SA National Accreditation System (SANAS) accredits laboratories, but the government's forensic laboratories in SA are not yet accredited.

Understaffing was a problem - the laboratories of the Department of Health, for instance, had a total of five analysts, compared to scores of analysts for one laboratory company in Britain.

All that SANAS accreditation means, he said, is that "the paperwork is in order and current and that there is traceability in the system". But if an analyst is in a hurry on a Friday, the result may still not be correct (as was apparently the case for the company which tested for Sudan Red for the Sunday Times recently).