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IRRADIATING OUR FOODS: TO ZAP OR NOT TO ZAP
(January 2004)

Everyone has read the stories.

- Luncheon meats and hot dogs contaminated with an organism called listeria caused diarrhea and blood stream infection;

- Eating rare hamburgers contaminated with an organism called E. coli caused severe diarrhea and, in some cases, kidney failure.

- Eggs infected with salmonella organisms caused an epidemic of diarrhea and fever.

The answer to preventing such episodes, according to some experts, is treating our meats, vegetables, poultry, fruits, and fish with huge doses of sterilizing radiation. I am considered a staunch opponent of food irradiation. I am not. But, I am opposed to food irradiation as public policy until the proponents and the manufacturers are willing to answer some important questions.

Would there be benefits from irradiating our foods? The answer is yes, but not nearly the benefit the proponents claim. There are some 200 million cases of significant diarrhea each year in the United States. Of these, about one-third are food related - but four out of five of these are due to unknown causes, most probably viruses, and, in these cases, food irradiation would probably have no beneficial effect.

So, irradiating our foods will not help the two out of three diarrhea cases that are not food related; and probably will not even prevent most cases of food-related diarrhea. A statement by a researcher from the Centers for Disease Control in October 2000 includes an estimate that 880,000 cases of foodborne illnesses and 350 deaths would be prevented by food irradiation. That would be only be a reduction of a little over 1 percent of foodborne diarrheal episodes, and well under 1 percent of the total 200 million significant diarrheal episodes in the United States each year. There would be a reduction by only 7 percent of the estimated 5,200 diarrhea-related deaths each year. That is a very modest benefit from zapping all our foods. Nevertheless, on the positive side, food irradiation would certainly prevent a significant number of hospitalizations and deaths due to food-related diarrhea.

Why then would anybody (especially an infectious diseases expert such as I) continue to oppose irradiating our foods. Radiating foods does not make them radioactive, but one major concern is the potential for chromosomal (genetic) damage to those eating the foods. There are only two relevant human studies, one carried out in India, one in China. In the Indian study, conducted in the mid-1970s, malnourished children were fed ordinarily processed wheat, or irradiated wheat; after a relatively short period of time, those fed fresh irradiated wheat showed chromosomal breaks that were not found in children given wheat that had not been irradiated.

This study has been criticized harshly because of the small number of children included and the methods used in conducting the study. The criticisms are valid but the study still raises disturbing questions about possible genetic damage. A decade later, a bigger study was carried out in China. The subjects were healthy young and middle-aged adults who were fed irradiated foods for three months. The Chinese investigators found no increase in chromosomal abnormalities. The Chinese study was published, in part, in the Chinese Medical Journal. My colleagues examined the data, re-analyzed it and found that those fed irradiated foods did have increased chromosome breaks at borderline statistical significance (p = .07).

So, taken together these studies are inconclusive, but they are worrisome. It would not really be a good idea to feed billions of people around the planet food that might cause chromosomal damage. And suppose the risk is greater if you start out undernourished; that would apply to about two billion people on this planet. Think of food irradiation as the equivalent of a new drug. Would any new drug be accepted for general use in the United States without doing our own studies if the only two relevant studies, both conducted in other countries, suggested the possibility of potentially dangerous adverse effects?. We need a meticulous study conducted by an impeccable scientific group, in which young and older adults and children of different ethnic groups and different socioeconomic status are given irradiated foods for two to three months, studying their chromosomes at regular intervals. If changes are found, the chromosome analyses should continue for a few additional months after stopping the irradiated foods to make sure the abnormalities disappear (as almost certainly they would).

That is not a difficult, lengthy, or expensive study. I have urged this on the industry for the last ten years, but they have not been willing to conduct it. If chromosome abnormalities do occur with short term feeding of irradiated foods, what might the risk of genetic damage be if people are given irradiated foods for years or decades? My own bet, by the way, is that the study would be negative; but, it has to be done.

Equally important is the issue of nutritional damage to irradiated foods. The proponents say this is a non-issue and should be ignored. They are wrong. There are plenty of studies showing vitamin loss after irradiation. The following is a quote from a report prepared for the Director of The Bureau of Foods of the FDA. “There is ample published evidence that a number of vitamins are labile to some degree when irradiated. Particular attention should be focused on vitamin A and carotene, vitamin E, vitamin C, vitamin B-12, thiamin, and vitamin B-6. Although other vitamins and essential nutrients must not be ignored, the aforementioned vitamins are noted because of published studies that demonstrate losses in irradiated products”. There are many data indicating the potential for nutrient damage after irradiation.

A Department of Agriculture study showed that irradiated pork lost some thiamin content, but if the pork was then cooked it showed greater additional thiamin loss compared to unirradiated pork that had been cooked.

The evidence is clear. Irradiation can destroy some vitamins. It differs from food to food and also depends on the amount of irradiation used. The bigger the dosage the greater the nutrient loss. The advocates of irradiation either issue a blanket denial or say why worry, our food supply has plenty of vitamins, so some loss in irradiated foods is inconsequential. Others suggest that everyone just take vitamin supplements.

What about the 36 million people who live in poverty in the United States. They have enough trouble getting adequate nutrition without being fed foods with deliberately reduced vitamin content. And what about the 36 million people over 65? About 25 percent of older people will show abnormally low blood levels of at least one major vitamin. That is why older people need a daily vitamin supplement. Should we be feeding them vitamin-damaged foods? And what about the billions of undernourished people on this planet? Shall we tell them we will provide them with foods with longer shelf lives, with less contamination, but at the same time foods that are less nutritious? For a lot of people that would be an unacceptable tradeoff.

Proponents argue that cooking also causes vitamin loss so why castigate radiation. They are correct about cooking also causing vitamin losses. However, most fruits and an increasing proportion of vegetables are eaten raw, so for those foods the analogy with cooking is inappropriate. Additionally, as I have indicated, irradiated foods when further processed (cooking, freezing) may have an excessive vitamin loss compared to non-irradiated foods.

There is a further problem. We do not know for fruits and vegetables which of the hundreds of substances they contain are responsible for the beneficial effects in offering some protection against some cancers, heart disease, and stroke. If we cannot yet identify the beneficial components of fruits and vegetables, how can we tell whether irradiation will damage these health promoting components? Obviously, the irradiation could damage them more than it does certain vitamins, less than it does to the vitamins - or not at all. We just do not know.

I have proposed that every time a food, for example strawberries, is irradiated that food be tested by an outside impartial group to determine how much loss of vitamins there is from the irradiation itself and then from the usual processing (in the case of strawberries that would be freezing and thawing). The results would then be placed on the label accompanying each packet of the food. For meats, nutrient content would be tested before radiation, after radiation and then after cooking. This would be compared with cooking alone. At least the public would know that the specific food had been treated with radiation and that some measurement had been made of nutrient loss, if any, during radiation and then during further processing.

The radiation industry wants to irradiate your foods and gradually increase the dosage (which will increase nutrient loss), but they know the public is nervous about the idea of zapping the food with massive doses of radiation. So, they plan to disguise the fact that the food has been irradiated.

The plan is, at first, to make the size of the label indicating the food had been irradiated smaller, and accompany the small lettering with a logo that looks somewhat like a smiling face or a flower. The wording will indicate the food has been treated by “cold pasteurization (irradiation)”. The wording is designed to take advantage of the fact the public accepts pasteurization (heat sterilization) of milk and other beverages. Then, after about two years, they will drop the logo and the word irradiation. All the small label will say is “treated by cold pasteurization”.

The idea is basically to fool the public. That is unacceptable.

I want to again make it very clear that I am not an implacable foe of food irradiation. Indeed, I think, used judiciously, it may be a useful technology to protect people from the contamination by microorganisms in some of the food items (especially fruits and vegetables) that are imported from around the world, and it may be needed for deli meats that are eaten cold. But if used, it should be only under well-defined and limited circumstances.

I shall continue to oppose irradiating our foods with large amounts of radiation until the questions about chromosome (genetic) damage and nutrient loss are answered and until the industry agrees to full disclosure by prominent labeling of each irradiated food item that is sold to the public - and the consumers should always be given the choice to buy either irradiated or unirradiated foods.

The food irradiation industry is likely going to make a lot of money. That is okay; but, until they answer the questions I have posed and agree to clear and prominent labeling, my advice when irradiated foods are introduced into your supermarket is “pass them by”.