The expert: Fredrick vom Saal, PhD, an endocrinologist at the University of Missouri who studies bisphenol-A

The resin linings of tin cans contain bisphenol-A, a synthetic estrogen that has been linked to ailments ranging from reproductive problems to heart disease, diabetes, and obesity. Acidity — a prominent characteristic of tomatoes — causes BPA to leach into your food.

2. Corn-Fed Beef

The expert: Joel Salatin, co-owner of Polyface Farms and author of books on sustainable farming

Cattle were designed to eat grass, not grains. But farmers today feed their animals corn and soybeans, which fatten up the animals faster for slaughter. A recent comprehensive study found that compared with corn-fed beef, grass-fed beef is higher in beta-carotene, vitamin E, omega-3s, conjugated linoleic acid (CLA), calcium, magnesium, and potassium.

3. Microwave Popcorn

The expert: Olga Naidenko, PhD, a senior scientist for the Environmental Working Group

Chemicals, including perfluorooctanoic acid (PFOA), in the lining of the bag, are part of a class of compounds that may be linked to infertility in humans. In animal testing, the chemicals cause liver, testicular, and pancreatic cancer. Studies show that microwaving causes the chemicals to vaporize — and migrate into your popcorn.

4. Nonorganic Potatoes

The expert: Jeffrey Moyer, chair of the National Organic Standards Board

Root vegetables absorb herbicides, pesticides, and fungicides that wind up in soil. In the case of potatoes they’re treated with fungicides during the growing season, then sprayed with herbicides to kill off the fibrous vines before harvesting. After they’re dug up, the potatoes are treated yet again to prevent them from sprouting.

5. Farmed Salmon

The expert: David Carpenter, MD, director of the Institute for Health and the Environment at the University at Albany

Nature didn’t intend for salmon to be crammed into pens and fed soy, poultry litter, and hydrolyzed chicken feathers. As a result, farmed salmon is lower in vitamin D and higher in contaminants, including carcinogens, PCBs, brominated flame retardants, and pesticides such as dioxin and DDT.

6. Milk Produced with Artificial Hormones

The expert: Rick North, project director of the Campaign for Safe Food at the Oregon Physicians for Social Responsibility

Milk producers treat their dairy cattle with recombinant bovine growth hormone (rBGH or rBST, as it is also known) to boost milk production. But rBGH also increases udder infections and even pus in the milk. It also leads to higher levels of a hormone called insulin-like growth factor in milk. In people, high levels of IGF-1 may contribute to breast, prostate, and colon cancers.

7. Conventional Apples

The expert: Mark Kastel, codirector of the Cornucopia Institute

If fall fruits held a “most doused in pesticides contest,” apples would win. And increasing numbers of studies are starting to link a higher body burden of pesticides with Parkinson’s disease.