Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Readers Check in With Questions About Vaccines and Cookie Dough

Hello again, dear readers! We hope that amid the rush (and, let's face it, occasional stress) of the holidays, you were able to enjoy the season. We thank you for making the time to keep our mailboxes full. We will get right down to business.

-- In response to recent columns about organic foods and pesticides, a number of you asked how to effectively wash apples, which regularly find their way into lunch boxes and snack trays. We did a bit of research and found a study published last October in the Journal of Agricultural and Food Chemistry that says a soak in baking soda is the most effective way to get rid of pesticide residue. According to researchers at the University of Massachusetts in Amherst, a 12- to 15-minute soak in a baking soda solution successfully removed common fungicides and pesticides from the apple peel. This worked better than rinsing with water or washing with bleach.

However, because some pesticides penetrate the skin, the conclusion was that the only surefire way to avoid the chemicals was to completely peel the apple.

-- In addressing the potential dangers of recent outbreaks of measles, mumps and chicken pox, we touched on the need to stay current with vaccines. Several of you wondered if, after initial completion of all early childhood vaccinations, follow-up vaccinations are actually necessary. The answer is emphatically yes. A child's immune system is not fully developed, and vaccination schedules are structured to address that. When subsequent boosters are called for, it's because they are needed to confer full protective immunity. If your family has fallen behind on vaccinations, get in touch with your family doctor. He or she will be glad to help you get back on schedule.

-- Another extremely popular topic in our mailbox, likely in response to all the cookie baking that took place over the holidays, was whether eating raw cookie dough is really dangerous enough to warrant a warning from the FDA. Although it's true that the risk of illness is small, it's real. That's because two ingredients in raw cookie dough -- eggs and flour -- can be contaminated with dangerous pathogens.

In the summer of 2016, it was discovered that multiple brands of all-purpose flour were contaminated with E. coli, a nasty intestinal bug that can cause serious illness. Add that to the known risks of contamination of raw eggs by Salmonella, and raw cookie dough becomes risky.

That said, if you can't reliably keep your little (or big) family members away from the mixing bowl, you can take steps to make the dough a bit safer. Regarding flour, check the Food and Drug Administration website for the latest information on any recalls. If your batch of flour is cited, dump it. As for eggs, consider baking with the pasteurized variety, which have been exposed to enough heat to destroy potential bacteria.

Some heat-sensitive vitamins, such as riboflavin, thiamin and folic acid, are lost as a result of the pasteurization process. However, when it comes to raw cookie dough, we suspect nutritional value isn't the main concern.

(Send your questions to, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)