DEAR DR. BLONZ: Lean ground beef costs quite a bit more than regular. The fat drains out when you cook it anyway, so is it worth it, health-wise, to buy the more expensive type? -- C.S., Kansas City, Mo.

DEAR C.S.: To best answer your question, we will need to do some math. Let's start with two quarter-pound patties of uncooked hamburger (113 grams each). The first is of meat that is 75 percent lean, and the second is 95 percent lean. The 75 percent lean meat contains about 28 grams of fat, 18 grams of protein, 85 milligrams of cholesterol and 66 grams of water. The 95 percent lean patty contains 5.6 grams of fat, 24 grams of protein, 70 milligrams of cholesterol and 83 grams of water. At this point, we see that the leaner meat has more water and protein, but less fat and cholesterol.

The cooking process will cause both patties to lose both water and fat.

The 75 percent lean meat drops from 113 grams to 70 grams in weight (a 38 percent decrease). After being cooked, it will contain about 13 grams of fat (a 54 percent decrease), 18 grams of protein (no loss here), 62 grams of cholesterol (a 15 percent decrease) and 39 grams of water (a 41 percent decrease).

The 95 percent lean meat will drop from 113 grams to 82 grams in weight (a 27 percent decrease), and will contain 5.4 grams of fat (a 4 percent decrease), 22 grams of protein (an 8 percent decrease), 62 milligrams of cholesterol (an 11 percent decrease), and 54 grams of water (a 35 percent decrease).

They both weighed the same before cooking, but after cooking, the 75 percent lean meat weighs 70 grams and contains 189 calories. The 95 percent lean meat weighs 82 grams and contains 137 calories.

The patty made from the leaner ground beef gives you more to eat, and while they both contain a comparable amount of cholesterol, the lean beef provides more protein and less fat.

As to which is worth it health-wise, much depends on the rest of the foods you have on your plate that day. Then there are other considerations such as your food budget, where the beef came from, and how that rancher treated the animals and the land on which the cattle were raised. Granted, this is big-picture stuff, but I believe it all deserves consideration.

DEAR DR. BLONZ: What is the bioavailability of the calcium carbonate in almond milk, given that there's no lactose in that kind of milk? And what's the bioavailability of calcium in real cow's milk if I pour it on cooked nine-grain cereal? Does the wheat in this cereal somehow limit the amount of calcium the body can absorb? -- R.L., Berkeley, Calif.

DEAR R.L.: There will be slightly less bioavailability with the calcium in fortified milk substitutes, such as almond or soy milks, than with the calcium in dairy milk. Breakfast cereals, when served with any calcium-containing beverage, enhance calcium intake by the very inclusion of that source of calcium. A whole-grain cereal may decrease calcium absorption to a minor degree, but many cereals are fortified with their own calcium. None of these factors should in any way be considered game-changers.

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: 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.