In a far-reaching assessment of the technology, the food safety body also appeared to conclude that chemicals formed in food as a result of irradiation were not a major concern. This is due to the low levels of the substances formed and the fact that the same chemicals are produced by other widely-used processing methods.

The significance of recent studies linking irradiated food to neurological problems in cats was unclear given the limited data, said the body. Further research was necessary to assess its relevance to human health but that the small amount of food irradiated in Europe meant there was no “immediate cause for concern”.

Refine process

The food safety watchdog’s update is the latest in a string of evaluations of irradiation in food, with the most recent assessment carried out by the Scientific Committee on Food (SCF) in 2003.

The latest opinion, published yesterday, was a combination of two EFSA committees. The Biological Hazards (BIOHAZ) Panel looked at the safety and efficacy of the method, while its chemical safety was scrutinised by the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF).

Experts from BIOHAZ backed the safety of irradiating foods but stressed it should be considered only as one of several food safety tools to be integrated into a full risk management plan.

“When integrated into an overall food safety management programme that includes Good Agricultural, Manufacturing and Hygienic Practices and HACCP, and depending on the dose applied, food irradiation can contribute to improved consumer safety by reducing food-borne pathogens in all the food categories and food commodities previously evaluated by the SCF,” said the committee.

The SCF previously had previously assessed the acceptable radiation doses - measured in KiloGrays (kGy) - for18 major food categories. The overall average dose ranged from a maximum of 1kGy for vegetables and cereals and 7kGy for camembert cheese to 10kGy for blood products.

But crucially both panels concluded that the efficacy of the irradiation dose to inactivate pathogens would be improved if a more refined approach was adopted. This should factor in not just the food type but also such aspects as the pathogen(s) being targeted and the reduction required. The physical state of the food – its water activity, fresh or frozen status and composition – was also key.

Changing food marketing practices and consumption patterns in recent years meant the previous classification did not identify all foods representing a potential high risk for consumers - with some ready-to-eat foods highlighted as one important example, they said.

“Since the dose applied may be limited by other constraints, the food irradiation process cannot always be designed on the sole basis of the food-borne pathogen of concern”, concluded BIOHAZ.

Chemical safety

The CEF examined the formation of chemicals such as hydrocarbons, furans, 2-alkylcyclobutanones, cholesterol oxides, peroxides and aldehydes and evaluated the hazards they posed.

The experts noted that the majority of these substances are also found in food that has been subjected to other processing treatments and are thus not exclusively formed by irradiation. The quantities in which they occur in irradiated food were not significantly higher than those being formed in heat treatments, said the panel.

The experts paid particular attention to 2-alkylcyclobutanones. Until recently these were only reported in irradiated food but a new study found they were also present in commercial non-irradiated fresh cashew nut and nutmeg samples.

The findings of other research linking the substance to DNA damage in vitro were also challenged.

“No in vivo genotoxicity studies are available," said CEF. “However, a genotoxic hazard in humans is considered unlikely by the Panel in view of the plausible indirect mechanism underlying the genotoxicity of alkylcyclobutanones in vitro.”

The panel also examined evidence linking irradiated foods and the neurological disorder leukoencephalomyelopathy. Concern had arisen after scientists found that cats fed mainly or exclusively with highly irradiated feed (>25 kGy) developed the condition.

Delivering a measured conclusion, the EFSA scientists said because no clear explanation in terms of risk assessment had been established, the threat to human health “could not be ruled out”.

But the committee added: “Considering that only a very limited quantity of food is irradiated in Europe currently, the Panel is of the view that there is not an immediate cause for concern. However, the relevance of the cats’ studies for human health should be clarified.”

EFSA said it couldn’t make an assessment on the allergenicity of specific foods following irradiation because current research data was inconsistent.