I called a number of bread makers to find out how long bread can be eaten after the last date of purchase. The answers varied all over the lot. What determines how long bread can be consumed safely after the last date of purchase?

The reason the replies are varied is that there is no absolute answer to your question. But we can give you two sound reasons to discard bread. The first is obvious signs of deterioration, particularly mold. Second are textural and taste changes related to the staling process. You, the consumer, must make judgments regarding both sets of criteria. Incidentally, contrary to popular practice, if carefully sealed, bread will keep better at room temperature than in the refrigerator.

I recently read an alarming story about the type of food poisoning associated with bluefish. Has something inherently dangerous about bluefish been discovered?

No. The outbreak you read about was the result of mishandling the fish. The problem occurs when a toxic substance builds up in improperly handled fish. It is called scombroid poisoning and is usually associated with fish of the Scombridae family, including tuna and mackerel. Scombroid poisoning also has been linked to other dark-flesh fish, such as mahimahi and amberjack. On occasion, isolated cases occur with bluefish production.

The toxin is not present in the fish as they are caught. For it to develop, generous amounts of the amino acids histidine must be available. These are abundant in dark-flesh fish. Also, microorganisms providing an enzyme that converts the amino acid to histamine must be present. These microorganisms are normally found on the surface of fish. Certain time and temperature conditions allow for this and perhaps other toxins to build up in the fish flesh.

Histamine, even in large amounts, is not toxic, so it is thought that other compounds form and have a synergistic effect. Unfortunately, once the toxin develops, no available method of preparation -- freezing, canning or smoking -- will render the fish toxin free.

Symptoms of the poisoning usually begin within a few minutes to a few hours after ingesting toxin-containing fish and last about four hours. They most commonly include headache, flushing of the face, a burning sensation on the mouth and throat, dizziness, nausea, abdominal cramps and diarrhea. A bright-red rash, hives and itching also may occur.

The exact nature of the mishandling, which caused the recent episode of illnesses in five individuals, is not clear. However, some of the fish, which had been frozen, was not used until four days after it had been put in the refrigerator to thaw.

The preventive message is simply this: Use fresh fish within a day or two after purchasing. If that is not possible, freeze it. But, when you do decide to thaw and use it, be sure to do so as soon as you can.

I was given a microwave oven for Christmas. Up to that time, I had ignored the entrees and dinners in the frozen-food section of the supermarket, but then decided to give them a try. I bought an enchilada entree after checking the nutrition labeling for sodium and noting that it was not much over 700 mg, a reasonable amount. However, I failed to observe that the portion described was only half the contents of the package. At first bite, I thought it tasted quite salty. That prompted me to reexamine the label, only to discover that the contents were expected to be two portions. Is there a limit on what manufacturers can call a portion?

No. When nutrition labeling went into effect 15 years ago, it was decided to leave the specification of portion sizes to the manufacturer. That is why two brands of an identical food can have different portion sizes. In most cases, portion sizes specified have been reasonable. Your example -- the case of the salty enchilada -- seems to be an exception.

The only real defense for the consumer concerned about diet is to check labeling information carefully. Also, if you feel strongly enough, you could write a letter to the manufacturer explaining that you believe you were misled. Who knows? Enough mail of this type might make companies sit up, take notice and decide that more reasonable labeling might be good business.

1988, Washington Post Writers Group