DEAR DR. BLONZ: What do you think about the safety of wood versus plastic cutting boards? I heard that wood dissolves bacteria when I was a student, but now I see many people using plastic cutting boards. What is your take? -- R.T., Oakland, Calif.

DEAR R.T.: We first had only wood, but then plastic came on the scene with claims that it was safer. A study conducted at the University of Wisconsin moved the focus back to wood, then the U.S. Department of Agriculture re-examined the issue and their results seemed to vindicate plastic. It is definitely an "up for grabs" issue, but there are some basic principles.

Wood can wick moisture away from contaminant debris inadvertently left on the board, and this can kill microorganisms. While plastic does not have that wicking action, it tends to be easier to clean, and you can toss it in the dishwasher. The take-home message is the importance of cleaning and periodically disinfecting any cutting surface. Allowing a board to dry between uses is also a plus. With wood there is also the need to pay special attention to debris removal so as to prevent any buildup of any blackening mold.

I also suggest separate boards for animal products and non-meat items. It is equally important to clean any cutlery that will be used on multiple items. If you are using towels to wipe off hands or utensils, be sure to use care with those, as well.

DEAR DR. BLONZ: How long after the date on the egg carton are the eggs safe to eat? -- B.B., San Diego

DEAR B.B.: You should take the dating message stamped on an egg carton literally. "Best if used by" will give you a few more days; "Use by" or "Expiration date" describes the recommended end of the line. The eggs don't turn toxic at the stroke of midnight, but they have already been lying around for a number of weeks, so it would definitely be time to use them up or toss them out.

It would be tough to say exactly when things would get dicey for any given carton of eggs, since much depends on the way they were washed, handled and stored as they made their way from the pen to your refrigerator. Then there is the issue of whether your refrigerator did a good job of keeping them at or below 40 degrees F. It is always best to toss them out if you have doubts or concerns. If you do end up using eggs near or just after their time is up, be sure to give them a good high-heat baking or cooking. That's always a good step to help eliminate microorganisms that may have taken up residence.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: Can eating carpaccio be considered safe? I know that it is made from raw meat or fish. The particular product I recently ate was veal dressed with salt, garlic and pepper, than quick-frozen at 0 degrees F and served very chilled. Is there any significant risk? -- N.C., New York

DEAR N.C.: Carpaccio is made from a number of raw meats or fish, and it is difficult to make any public health pronouncements when it comes to these raw foods. Not every serving is going to make you ill, but the risks are definitely there.

The villains are virulent microorganisms (bacteria, viruses and protozoan creatures) that contaminate food. Food is rarely sterile, so it's not unusual for fresh animal products to contain these microorganisms. The problem arises when a quantity of bad bugs sufficient to overwhelm the body's defenses manages to hitch a ride into your system because the food is served raw or undercooked. Carpaccio has no high-heat step to keep potentially dangerous microorganisms off your plate.

One cannot even say what percentage of servings can be considered safe. Some types may be more reliable than others, in that they are carefully selected, prepared rapidly and then immediately placed into an acid-based marinade to slow potential growth. But even with good practices, it is risky to say that any brand or restaurant offering will always be safe to consume.

In your particular case, if that meat had been contaminated before it was prepared, it does not matter how clean the dressing, freezing and serving operations might have been; there would still have been no intervening step to destroy the microorganisms that might be present. Salting, and use of garlic and pepper, helps to some degree. But again, it is not appropriate to generalize that this represents a solution and that all food prepared in this way would be safe.

It improves the comfort level when companies that sell such foods take specific steps to select, protect and monitor their products. This would involve routine screenings to check whether dangerous microorganisms might be present in any particular lot before the product reaches the consumer. If you insist on eating carpaccio, touch base with the supplier to see what steps are being taken with their particular product.

The best advice is to be wary when consuming high-risk foods. Exposure to food-borne infections can be life-threatening for small children, pregnant women, the elderly and those with weakened immune systems. It becomes less serious for those in good health, but even healthy individuals will have to balance the risks and decide for themselves.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

DEAR DR. BLONZ: I just read a book that says by blending fruit into a smoothie, you are not getting the benefits of the fruit's insoluble fiber because the blender completely destroys it. The book also says that not only am I not getting the fruit's full fiber benefit, but also the sugar from the fruit enters my bloodstream just as quickly as fruit juice. Is this true? Should I quit making smoothies? I get two of my daily fruit servings from my smoothie. Is there a better solution? -- K.S.D., via email

DEAR K.S.D.: I don't buy the argument that blending negates the benefits of the fiber in fruits (or vegetables or grains). The machine will most certainly reduce the size of fiber particles, but the fiber is still there. It is the unique way that the fiber molecules are bound together that's the key. Digestive enzymes help break down large compounds into ones small enough to pass through the absorptive surfaces in the intestines. Fiber is unique in that the human body doesn't have any enzymes to break it apart. We do, however, have the enzymes to effectively break down starch into its individual glucose units.

As a result, fiber gets to pass through the small intestine without being absorbed. The blender does indeed cut and shred, but there is no basis to fear that this process breaks down the molecular bonds that form the essence of the fiber.

Blending does effectively increase the viscosity (thickness) of the food as compared with a typical juice or with the product of a juicer, where the fruit's solids are not a part of the final output. Higher viscosity tends to slow the rate at which we eat, as well as the rate at which the stomach empties. Both these factors lead to less food being consumed before you feel full.

Eating fruits, vegetables and whole grains are the heart of what healthful eating is all about. One question associated with smoothies, which you mention, is whether consuming foods in this manner might cause the blood sugar level to rise more rapidly than eating the same foods in the whole, unblended state. The research is somewhat mixed on this matter, and considering the benefit of having these healthful foods in your diet, it makes sense to consider a few more specifics.

What, for example, are the ingredients in your smoothies? You say that you have been consuming fruits this way for a while. Is having smoothies as a regular part of your diet working for you? Do you have any health issues relating to blood sugar regulation? If so, then you should modify the components of your drink.

The great thing about the smoothie concept is the wide variety of wonderful sweet or savory recipes available, including the use of fruits, greens, grains, protein sources and spices (see tinyurl.com/kaduhn7). There are also plentiful recipes for those who want their smoothies strictly vegan (see tinyurl.com/lm4dk7y). As with any food, make it one part of a healthful "big picture." As always, eat slowly and enjoy.

Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.