Experts call for more research on semicarbazide

Calls to food manufacturers to develop alternative methods for sealing jars of food were voiced by the UK Food Standards Agency this week following a European scientific review on the presence of semicarbazide - a weak carcinogen - in foods.

In July this year the European Food Safety Authority​ (EFSA) said that semicarbazide (SEM) may have been found in certain foods packed in glass jars and bottles closed with metal lids sealed with plastic gaskets. The foods concerned included fruit juices, jams and conserves, honey, baby food, pickles and sterilised vegetables, mayonnaise, mustard, sauces, and ketchup.

As the toxicity of SEM is not well understood, the EFSA promptly called on an ad hoc expert group to investigate the issue further. Yesterday in Brussels the group, voicing its findings, said that while results are 'not conclusive at the present time, it has become clear that SEM is present in certain foods in very small quantities'.

It now seems likely that semicarbazide does migrate into food from the plastic gaskets used to seal glass jars with metal twist-off lids.

The expert European panel also said that there is evidence from animal studies that semicarbazide is a weak carcinogen but, because of the limited evidence, it is not possible to conclude whether or not semicarbazide may pose a cancer risk to humans. The risk, if any, according to the panel, is judged to be very small, both for infants and adults and the panel yesterday advised no change to current dietary habits.

Despite this, the EFSA is calling for quick action from the industry. It has recommended that the European Commission 'put in place a monitoring programme to ensure that industry implement alternative packaging solutions in a timely manner focusing on baby foods as an immediate priority'.

The food and drink industry in the UK has promptly responded, supporting the EFSA advice and presenting a new action. Martin Paterson, deputy director general of the Food and Drink Federation commented this week: "As a precaution, a joint food and packaging industry taskforce is now working with the authorities to eliminate SEM from the metal twist caps used with glass jars."​

"Our vigilance revealed through routine monitoring that traces of semicarbazide had been found in food and drinks sold in glass jars. We immediately brought this to the attention of the food standards authorities,"​ he added.

SEM belongs to a family of chemicals (hydrazines) which are known to cause cancer in laboratory animals. While semicarbazide has not been extensively tested for toxic effects, it may also be genotoxic - that is, it can damage DNA, the genetic material in cells.

"The presence of SEM is thought to be a result of migration from the plastic sealing gasket used in the metal lids (vacuum caps) of glass jars. This gasket plays a crucial role in maintaining the seal and ensures the safety of the product throughout its shelf-life,"​ said Peterson.

SEM is thought to be linked to another compound - azodicarbonamide (ADC) - used in the formation of the gasket and which has been used for decades.

"Manufacturers are committed to finding solutions that do not compromise the long-established safety record of food and drink in glass jars, nor introduce new safety concerns through hasty changes to current practice,"​ concluded the FDF deputy director general.