Back in grandma’s day, when everyone purchased their meat from a butcher and their veggies from a greengrocer, the only food contaminants encountered would have been a few particles of soil clinging to a carrot or a potato and, perhaps, one or two small fragments of bone adhering to the odd lamb chop. Both of these would simply have been rinsed away under the tap. Today, however, much of what we eat is processed before it arrives on our plates, and even that which has not been produced in a factory is likely to have been treated with one or more chemicals in an effort to enhance or protect it in some way.

As a result, the issue of contaminants present in food has steadily become a far more significant one. This, in turn, has made it necessary for both the growers of fresh produce and the producers of processed foodstuffs to introduce suitable measures to detect and eliminate them.

The offending items fall into one of three general categories. For example, they can be physical in nature and could be a fragment of eggshell, a fruit pit, or even a piece of glass. Where the presence of such items has not been excluded as the result of operator vigilance, these will often be removed when routinely subjected to straining for this very purpose.

By far, the more serious food contaminants, however, tend to be either chemical or biological in nature and, in products where these might present a potential threat, some more sophisticated form of testing will be required in order to eliminate their presence. As for the chemicals themselves, the main aim of the producer is to ensure that their concentration is kept within the acceptable limits set by local and international standards agencies.

For this purpose, it will be necessary to perform tests for some of the more common contaminants found in processed food, such as pesticide residues and the constituents of organic fertilizers. Where cleaning chemicals are used to sanitize working surfaces, these need to be rinsed well to ensure they cannot find their way into a company’s products. Consequently, their presence might also need to be excluded.

It is, however, the inappropriate biological content of edible products that causes both the producers and consumers the most concern. While the pesticide residues and other such chemicals that may occur as food contaminants can be tolerated in small quantities, it only takes a relatively small number of pathogenic bacilli to result in a serious infection, such as typhoid fever or listeriosis. Most South Africans will recall that an outbreak of the latter condition, in 2017, affected over a thousand consumers and claimed more than two hundred lives. Its origin was eventually traced to a batch of polony from a leading manufacturer of processed meats. An apparently minor glitch in their quality control procedures led to some major consequences.

When production demands are high, testing for bacterial food contaminants must be both reliable and rapid to avoid lengthy delays in releasing products into the distribution chain. Fortunately, the days when bacterial cultures were required and took at least 24 hours to provide a result have long since passed, thanks to the new sensitive and rapid test kits now available from IEPSA.

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