Q Many sources say the way to prevent salmonella poisoning is to thoroughly cook foods to destroy the bacteria. If heat destroys it, why are baked goods, such as peanut butter cookies, being recalled? Wouldn't the baking process have destroyed the bacteria?

A Yes, heat destroys salmonella, but the food has to be heated thoroughly.

When peanuts for peanut butter are properly roasted (typically 350 degrees), salmonella bacteria are killed. If, however, the peanuts aren't properly roasted, or if they are subsequently contaminated by bacteria during processing, then the peanut butter can harbor salmonella. Salmonella organisms can persist indefinitely in high-fat foods such as peanut butter, according to the Centers for Disease Control (CDC).

The reason peanut butter cookies are being recalled is that the cookies might not get hot enough throughout to kill all the salmonella if peanut butter contaminated the dough. With products such as crackers, the peanut product often isn't baked, but added as a filling after baking, so they're also being recalled.

In the current salmonella outbreak, the exact mechanism for contamination has not yet been determined, according to the CDC.

Includes information from the Minnesota Health Department

More on stinky wash machines

Several readers responded with additional tips for front-loading wash machines that develop a moldy odor:

• There is an amazing product on the market called "Smelly Washer," developed by a man in Savage and marketed around the world. (For details go to www.smellywasher.com.)

• Use a powder detergent; it's the liquid detergents that cause smelly washers.

• In addition to wiping out the washer and door gasket and leaving the door open between washes, remove the soap/bleach dispenser. Wipe it clean, and the area where it is housed, and leave it out to dry thoroughly.

Send your questions to Fixit in care of the Star Tribune, 425 Portland Av., Minneapolis, MN 55488, or call 612-673-7032, or e-mail fixit@startribune.com. Past columns are available at www.startribune.com/fixit. Sorry, Fixit cannot supply individual replies.