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Eurofins Food Testing UK’s Head of Microbiological Services, Catherine Cockcroft,

highlights the dilemma facing the food industry as technological advances mean it’s now possible to test for an ever-growing list of potentially harmful emerging organisms.

New threats for the food industry to seemingly worry about regularly feature in the media. But differentiating the true risks from the background noise is difficult, and addressing them within food businesses is even more of a challenge.

Those in industry must recognise the hazards relevant to their products, assess the risks and manage them through the use of food safety Hazard Analysis and Critical Control Point (HACCP) principles and pre- requisite programmes.

Microbiological testing can provide verification that HACCP and Good Manufacturing Practices are under control. However, with some of the emerging organisms of concern it may not be as straightforward to carry out verification testing, and even more difficult to interpret the results.

Food-borne viruses including Norovirus, Hepatitis A and Hepatitis E cannot grow or multiply on foodstuffs, but products such as bivalve molluscs, leafy vegetables and berries contaminated with water containing infected human waste can act as vectors for their transmission to humans via the faecal-oral route.

Resulting illness can vary from self-limiting gastrointestinal symptoms to more serious liver inflammations. While the true burden of illness attributable to contaminated food is not known, it is estimated that Norovirus is the most common cause of foodborne illness in the European region with close to 15m cases each year, causing more than 400 deaths (source: WHO estimates of the global burden of foodborne diseases: foodborne disease burden epidemiology reference group 2007-2015).

CHALLENGING Foodborne viruses testing in foods is challenging; particularly the recovery of low levels of strongly adherent viral particles which may be protected in microscopic crevices or within the digestive gland of bivalve molluscs. The best methods available may only recover 1% of the viral particles present from the food.

Complex molecular techniques detect the presence of viral particles, and results are expressed in numbers

24 | Tomorrow’s Laboratories

of viral genome copies. Detection in itself does not necessarily mean that the people consuming the food are at risk of foodborne illness. The infective dose from foods is not known, though may be as low as 10 viral particles. Furthermore, the presence of viral RNA does not necessarily mean that the particle is capable of infectivity.

WEIGHING UP THE RISKS Another consideration is the cost of performing the testing. Molecular techniques, unlike conventional cultural microbiology methods, are expensive and complex to perform, increasing the cost per test from a few pounds to perhaps a few hundred pounds.

Clearly, testing does not assure food safety, and producers / manufacturers already have procedures in place that minimise the risk of contamination of the foods by foodborne viruses.

Given the information gaps which currently exist, should food businesses already be testing for foodborne viruses to verify the effectiveness of the controls that they have in place? And if viral particles are detected on foodstuffs what remedial action should the food business take? Is there a risk that product will be removed from sale when it doesn’t present a true risk to the consumer. Or is the risk greater to the consumer if food businesses choose not to perform any verification testing.

At this early stage in the understanding of these micro- organisms caution is advised before rushing into full scale routine testing. Producers and manufacturers should anticipate how they will react to detection of these organisms, and be ready to enact those processes should the need arise. In the meantime, research to better understand these organisms, and to plug the knowledge gaps continues.

Methods for their testing are being refined and improved upon. In three to five years we may be in a position to include these organisms in routine verification testing of at-risk foodstuffs.

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