What is Food Irradiation ?

What is Food Irradiation ?

Food irradiation is a process in which food is exposed to high doses of radiation. Food is irradiated using radioactive gamma sources, usually Cobalt 60 or Cesium 137, or high-energy electron beams. The gamma rays break up the molecular structure of the food, forming free radicals. The free radicals react with the food to create new chemical substances called "radiolytic products". Those are know as "unique radiolytic products" (URPs) because they can only be found in irradiated products.

Irradiation is used to kill bacteria and insects which infest food and extends the shelf life of food, for example by delaying ripening of fruits or the sprouting of vegetables.

Health risks

Food irradiation can result in loss of nutrients, for example vitamin E levels can be reduced by 25% after irradiation and vitamin C by 5-10%. This is compounded by the longer storage times of irradiated foods, and by loss of nutrients during cooking, which can result in the food finally eaten by the consumer to contain little more than ’empty calories’. This is potentially damaging to the long and short-term health of consumers, particularly for sections of society already failing to obtain adequate nutrition.

When food is exposed to high doses of ionising radiation, the chemical composition of foods changes. Radiolytic by-products are often formed in irradiated food. Very few of these chemicals have been adequately studied for toxicity. Initial results of a current EU-funded research programme indicate that one such group of chemicals, called cyclobutanones, which are formed in irradiated fatty foods, can cause cellular and genetic damage in human and rat cells, and can accumulate in body tissues. More research is urgently needed to assess the risk to human health of consuming these chemicals.

Food irradiation does not inactivate dangerous toxins which have already been produced by bacteria prior to irradiation. In some cases, such as C. botulinum, it is the toxin produced by the bacteria, rather than the bacteria itself, which poses the health hazard.

Extension of the EU list of foods permitted for irradiation could mean that in future a significant part of the diet of consumers will consist of irradiated foods. The long-term impacts of this to health remain unknown. Far more research is required before exposing populations to such a diet.

Irradiating products such as mechanically recovered chicken meat, offal and egg white, could mislead consumers into thinking that these are safer. There is therefore a risk that they will then fail to take necessary measures to prevent cross-contamination. The risk of recontamination of food after irradiation is very serious as a near sterile food is an ideal medium for very rapid growth of re-introduced bacteria. Irradiated food needs even greater care when food handling in restaurants and in the home.

Misleading the consumers

Irradiating fruit and vegetables to extend their shelf life can mislead consumers by making ’old’ food look ’fresh’. The greater the age of fruit and vegetables, the lower their nutritional value, not to mention the effects of ageing on their tastes and flavours.

Consumers may be dangerously misled because irradiation also unavoidably kills off bacteria that produce warning smells indicating that the food is going ’off’.

The irradiation of some products, such as dried fruit and flakes or germs of cereal, often considered as health foods (eg muesli), could lead them to become misperceived by consumers as inherently contaminated food types.

Misuse of the technology

Food irradiation can and has been used to mask poor hygiene practices in food production. With irradiation, contamination can be sterilised. This reduces the incentive to clean up sloppy food processing operations - the industry is provided with a ’quick fix’ as an alternative to dealing with the sources of the problem. The consumer has a right to expect clean food, yet irradiation can lead to the increased production of food contaminated with dirt -’clean’ dirt.

Irradiation can be used to maintain or even worsen poor standards of animal husbandry. Overcrowding of animals whist rearing and prior to slaughter, as well as the use of cheap but inappropriate feeds, all contribute to contamination of animal products such as meat, poultry and eggs. Cleaning up these products at the end of the production line removes the incentive to improve animal welfare.

Breaches of existing labelling legislation have occurred in European countries, with the sale of unlabelled irradiated foods. Under these circumstance the consumer’ right to choice is flouted. Relaxation of irradiation standards could worsen this situation.

The safety of workers

Workers risk accidental exposure to dangerous levels of radiation, particularly at irradiation plants using radioactive sources.

The use of irradiation to sterilise meat at the end of the production line allows slaughter lines to be run at dangerously high speeds, since the greater contamination that occurs during high speed carving of carcasses can be ’cleaned up’ at the end of the line. This approach increases the risk of accidents and fatalities by forcing meat packers to work faster than ever.

Socio-economic costs

Food irradiation is not a low-cost method. Irradiation plants are expensive and could help large multinationals to eliminate smaller and more local producers.

Irradiation supports greater globalisation of food production and supply, putting at risk Europe’s local farmers, jobs in the European food processing industry, and rural economies around the world.

Environmental impacts

Accidents at radioactive irradiation plants have already led to radioactive spills and contamination of surrounding land and water resources. This could happen again.

The construction of more irradiation plants will lead to more transportation of radioactive materials, meaning increased risks of accidents and radioactive leaks over a wider area.

Irradiation allows food to be transported over greater distances, leading to greater air pollution and greenhouse gas emissions.

text published on ASECO website, april 2007