Deep-fried concerns increase food caution

ADELPHI, Md. -- The longer french fries and certain other starchy foods are fried or baked, the higher their level of a possible cancer-causing substance, new federal research suggests.

The substance, called acrylamide, made headlines last spring when Swedish scientists discovered that it forms in fries, potato chips and other high-carbohydrate foods cooked at high temperatures.

Several other European countries confirmed Sweden's discovery -- and now the latest batch of tests, revealed Wednesday by the U.S. Food and Drug Administration, shows that acrylamide levels vary widely even within the same brand of food.

For example, FDA scientists bought french fries at four different Popeye's restaurants and found a three-fold difference between the batches with the highest and lowest acrylamide levels. In tests of 25 seemingly identical bags of Lay's Classic Potato Chips, only two bags contained the exact same acrylamide level.

Acrylamide forms during traditional cooking methods -- whether you buy a ready-made food or fry or bake from raw ingredients in your own kitchen -- and it seems that the longer certain foods are cooked at especially high temperatures, the more acrylamide appears.

What does all this mean for consumers?

Acrylamide causes cancer in test animals, but has never been proved to do so in people -- meaning no one knows if higher levels in one food than another is a problem. FDA scientists stressed Wednesday that there's no reason yet for Americans to start avoiding certain foods for fear of acrylamide -- a message echoed by the food and restaurant industries.

Instead, concentrate on eating "a variety of foods that are rich in high-fiber grains and fruits and vegetables," said FDA food safety chief Janice Oliver.

Because acrylamide forms during traditional cooking methods, dietary exposure "is something that's been going on a long time," noted FDA senior scientist Bernard Schwetz.

But the big variability suggests acrylamide levels can be lowered in foods, FDA scientists told a meeting of the agency's food advisory board.

Scientists in FDA chemist Steven Musser's laboratory bought frozen french fries that, before baking, contained almost no acrylamide. Baking them for 10 to 15 minutes as the package directs caused a very slight acrylamide increase -- but none of the six scientists considered the fries done enough to be appetizing, so they stuck them back in the oven.

After 30 minutes of baking, the fries were golden brown -- and contained 120 times as much acrylamide. After 45 minutes, the now extra-crispy fries contained 400 times as much acrylamide as a mere 15-minute baking produced.

It's not just an issue for french fries. Even toasting bread increased acrylamide levels six- to 10-fold, the FDA testing showed.

In contrast, microwaving frozen french fries produced no acrylamide, Musser said. Likewise, other scientists say the chemical doesn't appear to form when foods are boiled. Nobody knows why, but perhaps those cooking methods aren't hot enough to produce the chemical reaction thought necessary to form acrylamide.

Acrylamide is used to produce plastics and dyes and to purify drinking water. Although traces have been found in water, no one expected high levels to be in basic foods.

Now scientists know it apparently forms when a naturally occurring amino acid called asparagine is heated with certain sugars such as glucose. Potatoes are especially rich in both asparagine and glucose, although foods from grains to even asparagus also contain it. Indeed, roasting asparagus produced very high acrylamide levels.

In contrast, the FDA tested hundreds of food samples and found products from infant formulas and baby food to frozen vegetables and meats acrylamide-free -- foods that either contain little asparagine or aren't cooked at super-high temperatures.

Food manufacturers insist their products aren't risky, but they're working with the FDA to understand acrylamide formation and to lower levels if possible, said Henry Chin of the National Food Processors Association.

It may not be easy, he cautioned.

For example, if frying temperatures are lowered too much potato chips turn out soggy. Also, levels of asparagine and glucose vary in different potato batches according to growing conditions and how long the tubers are stored raw, Chin said.