Everyone messes up a recipe now and then, but some mistakes in the kitchen can really cost you. Consumer Reports has some cooking mistakes that can waste money and even hurt your health.

  1. Don't put your kitchen knives in the dishwasher. The high heat of the machine's drying cycle can cause the blade and handle to expand and contract, so you could end up with a warped blade or cracked handle.
  2. Don't skip preheating your skillet when searing. If the pan's surface isn't hot enough, the proteins in meant and sugars in veggies won't brown and create a nice crust.
  3. Don't use nonstick cooking spray in nonstick pans. Over time is can damage your cookware, leaving a gummy film that can't be removed.
  4. Don't boil when the recipe says simmer. Even when you're crunched for time, it's important not to rush the cooking process. Foods will cook unevenly, meat can become tough, and the food at the bottom of the pot is likely to burn.
  5. Don't use your nonstick pans over high heat. Very high temps can break down the coating and create fumes that can kill pet birds and even cause flu-like symptoms in people.
  6. Don't run cold water over hot pots, pans and baking sheets. Over time the repeated expanding and contracting of materials can cause permanent warping and cracking.
  7. Don't dump frozen ingredients into your slow cooker. Slow cookers take time to reach a safe, bacteria-killing temperature. Starting with frozen foods can slow that process down even more, putting foods at risk of contamination.
  8. Don't ignore instructions to rotate baking pans. Many baking and casserole recipes suggest rotating pans during cooking to make sure the dish is uniformly cooked because home ovens might have pockets where one area gets hotter than another.
  9. Don't rinse meat before cooking. Washing raw meat and poultry can spread bacteria to other foods, utensils and surfaces.
  10. Don't rely on pop-up thermometers when cooking poultry. The device that comes with the turkey should not be your only guide because it's calibrated to pop at 180 degrees, past the ideal temperature, and you could end up with a dried-out bird.
  11. Don't refrigerate your tomatoes. Cold temperatures kill the flavor of tomatoes and create a mealy texture. This also stops the ripening process.

This information is from the June issue of Consumer Reports ShopSmart Magazine.