The packaging on the cheese said it was "nondairy," that it contained no milk, that it was made with rice. But when Andy Weir bit into it, the toddler with an allergy to milk swelled in reaction.

What'd his mom miss on that label?

"Casein," Diana Weir said.

Casein. Caseinates. Curds. Ghee. Lactoferrin. Whey. Nisin. In food-ingredient lingo, they all mean "contains milk."

From then on, Weir shopped with a wallet-size cheat sheet with more than two dozen "ingredients" her son, who could die from too much milk, should avoid. And even then, she couldn't spot every dangerous food. Sometimes, the milk was hidden in the catch-all "natural flavorings."

That starts phasing out this month with the dawn of a new federal food labeling law: the Food Allergen Labeling and Consumer Protection Act. The law requires that, as of Jan. 1, companies state in plain English any ingredients that contain proteins derived from milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat or soybeans.

Though medical research has found 160 sources for food allergies, these eight are responsible for 90 percent of allergic reactions.

"It's been a long time coming where label reading is easy enough for a 7-year-old to read it," said Anne Munoz-Furlong, founder and CEO of the Food Allergy & Anphylaxis Network, which lobbied for the law. "We're very excited."

So is Weir, whose son Andy is now 9.

Weir said she eventually committed the cheat sheet to memory, but she looks forward to easier reading in the aisles.

"It'll be much easier now. If I see the word 'milk' then I don't have to read all the ingredients," Weir said. That food just goes back on the store shelf.

Spotting these ingredients is becoming increasingly important in America, where the number of people with food allergies appears to be growing. The number of peanut allergies alone doubled from 300,000 in 1997 to 600,000 in 2002, according to the allergy network.

"There are more people with food allergies than there were a decade or two ago, though we don't know why," Munoz-Furlong said. "We believe part of it is better public awareness. We used to call some children sickly, now they're getting proper diagnosis."

Another theory floating about is the hygiene hypothesis, that we've done such a good job getting rid of things the immune system is designed to attack, that in some it is now turning on elements of our diets, she said. There are other theories as well.

Whatever the cause, Andy Weir is now one of 11 million Americans who suffer from food allergies. While some food allergies may raise a rash or trigger eczema, others such as Andy's can cause the body to shut down and swell, closing airways and possibly stopping the heart - the kind doctors call anaphylactic shock.

And the only way to treat these allergies is to avoid the trigger.

"It sounds easy, but it's virtually impossible not to have some commercially prepared food," Munoz-Furlong said. "When a doctor makes a diagnosis, they say, 'Avoid wheat or milk or egg.' They use simple words. Those are not the words used on product labels."

And the allergens can be in places shoppers might not expect.

Milk proteins in canned tuna. Wheat products in ice cream. Soy in cereal.

These first few months promise to be the most challenging for those trying to avoid these foods. Although the law kicked in Jan. 1, it doesn't apply to food already on the shelves. And some of that food has a shelf life of nearly two years.

So two bags of cookies sitting on a shelf. One is labeled under the new rules. One is not. Buyers will have to scan the entire label to be sure.

Even when the new labels are everywhere, some worry.

"You have to read every label all the time," Weir said.

Andy had to pass on Tyson's chicken nuggets for a spell when the company changed its recipe to include milk, she said. "When I talked to the company, they said they'd gotten a lot of complaints. Eventually, the company stopped using the milk and nuggets returned to the Weir refrigerator.

"It can be a false sense of security," one Boca Raton mom said of the labeling.

Robin Egerman's son and daughter have deadly peanut allergies. For years, they ate Nabisco Mallomar graham and marshmallow cookies, which were some of the only peanut-free cookies. Then Nabisco changed manufacturing plants and the label warned that they could have been contaminated by peanuts, not a regular ingredient, Egerman recalled.

"They didn't eat them for a whole year. I kept calling Nabisco and calling. They eventually moved it and they ate Mallomars again," Egerman said.

Cross contamination is the next target of the food allergy network, Munoz-Furlong said.

Food labels often say the product "may contain" an allergen, though it is not an ingredient. But there's no standard rule for what merits the warning. A candy bar may warn that the bar may contain nuts because a) it sat on the same conveyor belt as a food containing nuts, b) is in the same plant or building as nuts or c) because the company's lawyers think its a good idea to protect from lawsuits even though there isn't a nut in sight, Munoz-Furlong said.

Thus, somebody already on a restricted diet has even fewer choices.

There are no standards for cleaning equipment to prevent this cross contamination either, she said.

In the meantime, many parents in Florida are embracing another new law that went into effect this month: Children who could go into anaphylactic shock because of an allergic reaction will be allowed to bring an EpiPen to school: a small needle that can deliver a dose of life-saving epinephrine.

Do you know what's in your food?

The eight most common food allergens may seem easy to spot, but they can be hiding in all sorts of food as filler or flavoring. In the grocery store:

- Tuna: Some brands of canned tuna contain milk products; others have soy.

- Peanut butter: At least one brand contains soy.

- Ice cream: Some brands have wheat or soy.

- Nondairy creamer: It may say no milk, but that doesn't mean no milk products.

- Worcestershire sauce: Can contain fish flavoring from anchovies and wheat.

- Imitation crab: It may be fake crab, but it can have flavoring from real shellfish. It also may contain wheat.

- Hot dogs: Can contain wheat and/or milk.

- Egg substitutes: Can contain real egg whites.

- Barbecue sauce: Can contain tree nuts, peanuts and/or wheat

- Chocolates: They may not have nuts in them, but they could have been contaminated during processing. Some also contain wheat.

Source: The Food Allergy & Anaphylaxis Network, www.foodallergy.org

(C) 2006 The Palm Beach Post. via ProQuest Information and Learning Company; All Rights