Irradiation in Food

America’s Food and Drug Administration, one of the strictest regulatory bodies in the world, has recently approved the use of irradiation to kill certain parasites in pork. Later this year, it is expected to give approval for its use to kill insects in fresh fruit and vegetables.

Ultimately it will all be down to whether the consumer will buy it. And this is not the only headache food scientists are having meeting the consumers’ demand for a hasty prepared meal that is also fresh.

Take salad. With just a few minutes chopping here and there, preparation can surely not be a problem, even for the most hardened advocate of the TV dinner. But it is a nightmare for the food industry.

How do you keep it fresh, especially when in the form of a ready meal? Because it is mixed up, chopped plant material, it is one of the most unstable things to deal with. “Cut surfaces greatly increase the respiration”. says Dr John Geeson, head of fruit and vegetable storage at the Norwich-based Food Research Institute. With mayonnaise it is even worse as this interacts with the plant structure.

Food scientists are dealing with living organisms, whose own chemistry leads them to deteriorate. And they all tend to be different: “All different fruit and vegetable products have different rates of respiration”, says Geeson. Cauliflower and sweet corn positively pant, breathing 100 times faster than onions. Then there are external forces of bugs, mold and bacteria.

So the wrapper and gases that are used to package even the most wholesome of apples are under scrutiny. ‘The apples look natural, but the wrapper is a clever combination of polymers, and inside is a clever combination of gases to make it last. This is called modified atmosphere packaging and will vary in accordance with the idiosyncracies of different foods.

Red set and wet fish, for instance are regarded as “relatively dead”, and need a relatively impermeable wrapper, injected with the right mixture of oxygen, carbon dioxide and nitrogen. Fruit and veg are more of a challenge, needing a more permeable wrapper so they can breathe.

Sainsbury, Britian’s largest retailer of fresh fruit and vegetables, is undertaking extensive research into modified atmosphere packaging. It has also been introducing new cooling methods.

One of these, vacuum cooling, is being used in the packaging of lettuce. By cooling rapidly in a vacuum, there is a quicker evaporation of surface moisture and heat.

Sainsbury is also undertaking a rolling review to see which foods can have artificial preservatives removed. This is another result of changing consumer tastes.

Why have tastes been changing? Mintel, the market research organization has recently published what is claimed to be the first report on the “ready meal” market in Britain. Convenience meals – be they in cans, dehydrated, chilled or frozen – are now a pounds 10 billion market, of which ready meals are a small but rapidly growing sector. The most significant reason for this is seen as the emergence of women as breadwinners. “Cooking, particularly of the recipe book or experimental variety is becoming a leisure pastime which can be indulged in only occasionally and as a treat”, the report says. More people are living on their own, and there is more eating out.

The traditional meat and two veg is firmly out. Micro-wave ownership, now restricted to 10% of British homes, is increasing rapidly, and estimated to grow by 40% – some 1.4m units, this year. The demand is for case of shopping and little or no preparation.

And Mintel suggests that the social image of ready meals may be changing. Traditionally it has been seen as down market, but increasingly this is not the case with chilled meals.

Not only is there a demand for convenient food that is also fresh, but there has been a marked growth in the demand for ethnic meals. The demand for tinned food continues to fall.

But consumer taste can work both ways. At Leatherhead, scientists have identified the way the energy-forming enzyme in the micro-organisms which can cause bacon to go off is controlled during the curing process. It should be possible to learn more about the micro-organisms responsible for deterioration in bacon and manipulate them so that they behave themselves. This could replace the injecting of a strong salt solution containing nitrate into bacon as a way of killing the bugs. It may then be safer, as some scientists have linked nitrate to cancer. But the end product would look and taste so different to today’s bacon, that the consumer may never buy it.

Later this month, KP will be launching what it claims to be the first-ever low-fat crisps, involving a new production process. Which may still not be everyone’s idea of jungle fresh but must be seen as a part of the same trend.

The biggest impact of the new food technologies will be on the way familiar food is prepared, rather than the development of completely new foods. It will give manufacturers a bigger armory of techniques.

Ultimately, it stands to give a completely new meaning to the terms “fresh” and “unprocessed”. Products which appear that way will have been subjected to some of the most sophisticated of technologies.

Economics and tastes are increasingly militating against the concept of fresh food in its traditional sense.

“Logically”, says Mintel, “there would be nothing to prevent ready meals from broadening the staple food of advanced societies and making cooking a thing of the past.”

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