DEAR DR. BLONZ: I have a follow-up suggestion to the recent column on storing bread in the freezer. Like the previous letter-writer, I live alone, and I like to cook and freeze leftovers in single-serving portions. With my bread, I usually double-wrap the loaf: I put the original package in one of the larger plastic sleeves that come with the daily paper, then twist-tie it shut after making sure all the air is out of the bags.

Now for my question: Does freezing milk affect its quality or safety? I balk at paying almost as much for a quart of milk as I do for a gallon. I have a lot of freezer space, and have been freezing milk in quart mason jars. I’m especially careful to leave at least two inches of space at the top, between the milk and the lid, to allow room for expansion of the liquid as it freezes. If you violate this principle, I’ve learned, the glass jar is likely to crack. Is milk safe to drink after having been frozen and then thawed slowly in the refrigerator? -- J.W., Tucson, Arizona

DEAR J.W.: Your bread-freezing technique sounds great. It is always gratifying to find second-generation uses for the serviceable plastic bags that come into our possession.

Freezing is a safe and acceptable way to store milk. Changes in nutritional value are negligible, but there may be a few minor changes in the way the milk appears and tastes. The freezing process can cause a breakdown in the homogenization, which is the process that distributes the milk fat evenly throughout the milk. Of course, this will not be an issue with nonfat milk; with other types, however, an occasional drop of fat may be seen floating around. Give the milk a good shake before drinking.

The taste and appearance changes depend on the speed at which the milk is frozen. A slight change in taste, and/or some loss of color, is possible. These are very minor changes, and the milk remains a wholesome food. A good rule of thumb is: the faster the freeze, the smaller the damage.

I recommend that you put your well-sealed containers next to the freezer wall or on a metal shelf, where they’ll freeze quickly and remain solid for the duration of their storage. Remember, also, that because milk is a rich source of nutrients, it provides an ideal food for bacteria and other microorganisms. Pasteurization helps destroy most, but not all, of the bacteria present at bottling. Freezing doesn’t destroy microorganisms, it just suspends or slows their growth. Keep in mind that the quality of a defrosted milk, or of any other frozen food, will be no better than it was at the time it was frozen.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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 am at a conference about food and cookware, and one chef was leading a discussion on the topic of eating meat. She said that most of the meat we eat is muscle -- for example, steak is cow muscle. During a subsequent conversation, I brought up this subject and another chef immediately disagreed, saying that we are eating the “fleshy part,” whatever that is. (There was no time for any follow-up questions or requests for clarity.) Would you be so kind as to elaborate a little? -- W.L., via email

DEAR W.L.: Steak and other “muscle meats” do come from the muscle tissue of an animal. “Flesh,” as it refers to meat, can mean soft tissue such as muscle, but also fat or organs such as the liver or kidneys. But keep in mind that “flesh,” as a generic term, can refer to animal tissues in general. Hope this helps.

DEAR DR. BLONZ: I was in a natural foods store looking for an alternative to regular coffee. I was told about “ganoderma,” which is made from an extract of ganoderma lucidum -- a concentration of six species of red mushroom. The plus side, as it was explained to me, is that it has excellent nutritional benefits and the flavor of coffee, but with a minimum of caffeine. I am having a difficult time finding much information on ganoderma. While this supplement was flavorful, I would like to know more about what I am ingesting. -- S.C., Milwaukee, Wisconsin

DEAR S.C.: Ganoderma lucidum is the Latin name for a species of reishi mushroom. This mushroom has long been used in Chinese medicine, and other natural medicine traditions, for enhancing the immune system. I have heard of the reishi being taken as a tea or dried as a dietary supplement, but have not tried it roasted as a coffee substitute.

Some thoughts: Mushrooms are complex organisms, and there are many different species. Some types have wonderful culinary uses, while others contain components that have medical effects. And there are a small number of mushrooms that contain powerful toxins. As is often the case with naturally occurring compounds, there can be variations from harvest to harvest. All this translates to a lot of unknowns about the precise identification and level of active ingredients.

Then there are the issues of changes that could take place during roasting. The product is being touted as providing benefits from the fresh mushroom, but is there evidence that the substances in the whole mushroom remain efficacious after roasting? If there are active ingredients, are there possible interactions with health conditions, medications or other dietary supplements?

Finally, if this is to become your regular breakfast beverage, are there issues with chronic usage? All this might come across as overly cautious, but it makes sense to have a cup of consideration when something new is being tossed into the mix. Coffee has had its popularity ups and downs (we are currently in an “up” phase), but its components are well-studied, and it’s been around for a while.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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 live by myself and find it difficult to use up an entire loaf of bread before it dries out and becomes stale. I have tried storing bread in the refrigerator, but it never tastes the same. What is it about refrigeration that ruins bread? -- J.W., Las Vegas

DEAR J.W.: Bread turns stale as its starches undergo changes in structure. Although stale bread has a dried-out appearance, a loss of moisture is not the complete explanation -- a loaf will even turn stale in a well-sealed, never-opened package. Temperature, it turns out, is a key.

There are two main types of starch, or carbohydrate, in bread. Over time, each will change from a random to a more rigid arrangement. The first starches set up as a freshly baked loaf of bread cools to room temperature. If you have ever attempted to cut into a loaf right out of the oven, you’ll recall that doughy texture before the first starch sets up. The setting up of the second starch takes about a week. As that second starch changes, the texture of the bread shifts from soft to hard -- or as we call it, stale.

While refrigeration extends the shelf life of many foods, the second starch tends to set up faster at refrigerator temperatures. Your bread could turn stale in about a day. Refrigeration is not recommended for the storage of any raised bread product.

It’s unfortunate that sandwich vendors tend to store their premade sandwiches under refrigeration, but it does make sense: A slight staling of the bread is the price to keep the sandwich’s contents fresh. If buying a pre-made sandwich, try to get one that was made earlier that day.

As for the bread you keep at home, one solution is to look for breads that use preservatives called emulsifiers. They can slow down the setting up of starch and effectively extend shelf life. The most common emulsifiers used in bread, the monoglycerides and diglycerides, are effective yet harmless additives.

Freezing may be the ideal solution for your issue. Freezer temperatures are cold enough to keep the second starch from setting. If you are unable to get through a loaf before it goes stale, consider splitting your loaf and storing half in the freezer. However you decide to store your bread, make sure the package is always well sealed.

DEAR DR. BLONZ: Carrots in the refrigerator get soft and flexible after a few days, and eventually they shrivel. When are they no longer safe to eat? -- B.B., Chicago

DEAR B.B.: Carrots are a root crop, providing the route by which the water from the soil is taken up and transported to the rest of the plant. The fibrous part of the carrot contains flexible little compartments that hold water until needed by the rest of the plant above.

When the carrot sits, exposed to the air, the water evaporates. Over a matter of days, this will result in the more flexible vegetable you described. Eventually the carrot will wilt and rot. To retain moisture and firmness, carrots should first be washed, the excess water shaken off, and then placed in a plastic bag in the refrigerator crisper. Also, if you buy carrots with greens attached, remove them after purchase, as they tend to draw the water out of the carrot.

Carrots can be considered safe to eat as long as they’re not discolored, overly shriveled or slimy in feel. If a carrot has only lost some of its firmness, it can often be brought back with a soak in ice water.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 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.