Gamma, Egg and Chips

Food irradiation has the power to destroy bacteria, micro organisms, viruses and parasites that might be present in food and as such could be a potentially invaluable weapon against the global food crisis. Yet, since its inception in the early 1900s, the process has faced heavy regulatory restrictions worldwide and negative publicity.

Over the years, the global acceptance of pasteurised milk, advances in technology and notable positive regulatory developments have softened food irradiation’s public image, although its progress overall remains at best tentative. Conflicting opinions on which specific food products should and can be irradiated, the best technology for irradiating them and how the subsequent irradiated products should be labelled have divided industry and countries alike.

Currently, food irradiation is allowed in 40 countries which are estimated to irradiate about 500,000 metric tonnes of food each year. A range of food irradiation machine manufacturers and food irradiation service centres – where food manufacturers send products for irradiation – are scattered across the globe. In Europe, about 25 different food items are permitted for irradiation, most notably spices.

In the US, however, permitted items are regulated by the Food and Drug Administration (FDA), which in recent years has permitted a the irradiation of a range of fruits, vegetables and meats. Subsequently, the food irradiation market has opened its doors to the irradiation needs of exported food products arriving from Asia and South America.

Three technologies dominate the sector: gamma, electron and x-ray. Each method brings its own unique attributes and flaws. Gamma processes rely on the use of radioisotopes, generally Cobalt-60, which allows for deep product penetration.

Similar to gamma radiation, x-ray features deep penetration by using photon radiation of a wide energy spectrum, with the added benefit of using an electronic source that stops radiating when switched off. Electron irradiation – otherwise known as e-beam – uses particulate radiation which means the electrons have a cross section much larger than photons, offering less product penetration.

The differences between these technologies, however, are a further dividing point for the industry.

The X factor

IBA Industrial first began manufacturing electron beam irradiation equipment in the 1950s and recently began developing x-ray accelerators. The company is a strong advocate for researching technologies that can be used for food irradiation. IBA Industrial sales manager Loïc Loiseau is quick to highlight recent breakthroughs:

"Electron technology has been used for food irradiation for a long time now, but the penetration is not particularly good. X-ray technology, however, has very good penetration but industry accelerators struggle to produce enough kilowatts required to power them," he says.

"Eight years ago we therefore redeveloped the Rhodotron – an x-ray accelerator capable of combining the necessary power and energy needed for effective food irradiation. The machine can be used for sterilisation and disinfestation purposes."

Developed by IBA Industrial’s research team in Belgium, Rhodotron represents the next generation of x-ray food irradiation machines, capable of treating entire pallets of food per irradiation session.

"The market has reacted very well to the Rhodotron," Loiseau says. "When it comes to the food industry, the issue is more about how the consumer will react. Consumer attitude is a bit delicate when it comes to food irradiation, mainly because many do not fully understand the difference between irradiating using radioactive and electricity sources. Governments and food hygiene experts, however, have met the development of X-ray technology with a lot of enthusiasm."

Given the niche nature of food irradiation, the focus for most manufacturers or suppliers - including IBA Industrial - tends to fall on the demand for medical equipment sterilisation. Yet in spite of this, IBA Industrial has witnessed a notable global increase in sales during recent years. Rhodotron in particular has experienced particularly strong demand in Europe and Asia, the latter being a direct result of the increase in exported irradiated food products to the US.

A difficult label to bear

Currently, irradiated food products sold in Europe and the US are legally required to have labels informing the consumer of its irradiated past. Such a fact has proven to be a controversial issue for food irradiation manufacturers.

"Food irradiation is the only technique that can kill E. coli, which is responsible for about 73,000 infections and 61 deaths each year in the US. It is also one of the most effective techniques for treating food infestation, meaning if you irradiate a kilo of rice, for example, then three years later the kilo of rice will still be in good condition. Food irradiation could therefore help to avoid large food crisis’s that occur from bad harvests," Loiseau says.

"But food irradiation is far from becoming a standard global practice, largely down to customer acceptance. This will not change unless the governments alter current labelling obligations, which fail to differentiate between the different irradiation processes. I believe the general public is being misinformed and that the labelling should distinguish between food products irradiated by radioactive materials and those irradiated by electricity."

Companies that rely on gamma technology, however, strongly disagree. The Florida-based Food Technology Service Inc (FTSI) first began irradiating food using gamma radiation in 1992. Predominantly serving the domestic demand for treating tropical fruits and vegetables, the company’s president and CEO Richard Hunter believes the abelling of irradiated products should be the same for all techniques.

"There are some people from within the food irradiation sector who would like to see different labelling for non-radioactive sources as they see it as a competitive advantage. In reality that is not true and every industry regulation that applies to gamma radiation, applies to x-ray or e-beam radiation too," he says.

"The reality of the labelling issue in the US is what the FDA describes as a ‘need to know’ basis not a ‘consumer right to know’. This means the consumer must be made aware of the irradiation treatment as it has altered the storage characteristics of the product, which in most cases is to make it last longer."

Radioactive response

According to FTSI, 70% of food irradiation worldwide is achieved using gamma treatment. Hunter says he believes the technology is overall historically more proven then the other two techniques and more acutely identifies it as having far greater penetration then e-beam while offering stronger reliability then x-ray. "Gamma radiation is a proven process that is implemented in about 130 facilities worldwide. As it is capable of such powerful penetration, the technology is also more economical," Hunter says.

"Most people immediately equate gamma with radioactivity, but it is simply a method of generating energy, the same way e-beam is a machine generated. In general though, I think the public is either unknowing or unconcerned when it comes to food irradiation. In the US, the FDA is responsible for regulating food irradiation and this gives the public confidence. I believe if they are given solid unbiased information, most people are accepting of the process."

As a food irradiation service centre, food manufacturers deliver supplies of food to FTSI’s 23,600m2 facility for treatment. Typically the process takes between 40 min to 60 min depending on the product, before it can be returned directly to the food manufacturer.

In the case of FTSI, such products are mainly limited to tropical fruits from South Florida that are being treated in order to prevent the spread of Caribbean fruit flies in to other warm weathered states. This subsection of the market demand has served FTSI well in recent years and Hunter believes progress is being made on a global scale.

"Worldwide the use of irradiation with fruits and vegetables has increased significantly. Facilities are being constructed in Mexico, Thailand and India, the latter in particularly benefiting from the recent US approval of imported irradiated mangoes," says Hunter.

"I think overall it is a steadily growing business but not rapid. A strong period of growth or transition will only occur if more fruits and vegetables, in particularly leafy vegetables, are allowed to be irradiated. There is strong evidence to suggest that many food borne illnesses can be linked with uncooked fruits and vegetables – food irradiation could offer a strong safety stamp for these products in the future."