What Do You Know About Preserving Milk and Eggs?

In what follows, Mrs. Karam Tanir Shouman puts to the agricultural engineer Hasan Shouman a set of useful questions on preserving milk and eggs. Every wise lady would do well to give them the attention they deserve.

Q — We have heard a great deal about the sound scientific methods for cleansing milk of microbes without its losing any of its beneficial qualities. But these methods are difficult to apply in the modest kitchen, such as the kitchens of most of our ladies. What, then, is the scientific method by which we can do the same work and reach the desired result of purifying milk without going to trouble or spending money on apparatus more suited to laboratories? What is the method at once ideal and simple, so that our ladies can follow it at home to boil milk without losing its natural qualities and benefits?

A — Boiling milk is almost the only method of treating it in the home, unlike the case in most European countries. This familiar operation is carried out by setting the vessel directly over the fire until the surface of the milk rises, whereupon it is taken off the fire and the vessel is left uncovered to cool.

Q — And what is the harm in this method? You know, of course, that most of us use it when we buy milk?

A — You will observe that the milk does not actually boil. Rather, it is merely heated, and that method does not destroy the microbes. It has been found that the microbes contained in the skin are, generally speaking, less affected by heating than those microbes present in the milk itself beneath the skin. Therefore, to ensure the destruction of disease-causing microbes, the milk must be stirred while boiling, so that its contents are evenly distributed and all of them are exposed to a high temperature.

Q — And do you think it necessary to cover the milk vessel after boiling?

A — Leaving it uncovered exposes it to contamination by flies, which sometimes carry dangerous disease microbes into it. And the milk must be cooled at once. One of the chief causes to which the spoiling of milk is attributed is its not being cooled with the necessary speed, for it is often left after heating to cool of its own accord.

Q — And is there anything wrong in that?

A — Yes; the result will be that the remaining microbes multiply rapidly once the temperature falls to the degree that suits them, for moderate warmth helps microbes to multiply.

Q — Let us suppose we have finished boiling it and cannot put it in the refrigerator, since no such luxury exists in most of our modest homes. How do we make up for this unavoidable lack?

A — We must take care to cool it under running water immediately after boiling. Then we keep it at the lowest possible temperature, especially in summertime; and care must also be taken that the container into which it is transferred after boiling is clean.

Q — I see that you find nothing in this method that violates the rules of health for preserving the benefits of milk!

A — This boiling process does not affect the properties of the milk. But it does give it a particular odor, affects its constituents to a certain extent, converts part of its soluble salts — calcium phosphate above all — into an insoluble substance, and damages some of the vitamins it contains, especially vitamin C. All these changes reduce its usefulness. I advise mothers not to feed their children constantly on boiled milk, since it has lost some of its essential elements.

Q — And do you consider this the only method, in its simplicity and its practicability, that can be followed in the kitchen?

A — The best of the simple methods followed in boiling milk is to fill it into small bottles which are closed and placed in a vessel, resting on a piece of wood laid on the bottom of that vessel. Very hot water is then poured into the vessel until it reaches the level of the milk in the bottles. It is set on the fire until the water boils. Then it is taken off and set on a hot surface or near the stove for a quarter of an hour. After that it is moved to the washing basin, where the hot water in it is replaced by cold, the water being kept running into it for five minutes; finally the bottles are left in the cold water, closed, until they are needed.

Q — Thank you. And I wish you could help us in another aspect of economy in kitchen expenses. What is the method by which the housewife can make sure that eggs are fresh, so that she is not forced to buy spoiled ones? You know, no doubt, that the prices of eggs — this essential food — have risen very high.

A — It is difficult for a lady to recognize a fresh egg with the naked eye. That requires experience and practice. But inside the egg, at its lower end, there is a hollow known as the air chamber, and the fresher the egg, the smaller this hollow. You can recognize an old egg by the sound its large air chamber makes when you shake it in your hand.

Q — And the water-and-salt method? I have heard of it before.

A — That is the specific-gravity method — that is, the ratio of the egg's weight to the weight of an equal volume of salted water. If we add to a liter of water 125 grams of salt, or the equivalent of about half an uqiyya, we obtain a specific gravity close to the specific gravity of an egg. In this case an egg one day old can be recognized: if it is placed in this liquid, it remains lying horizontally at the bottom of the vessel.

Q — And if it is older than that?

A — Its weight will decrease by about a gram each day. And you can recognize fresh eggs if they rise in the salted water, for they usually float on the surface of the water.

Q — And what is the best season for preserving eggs?

A — It is advisable for housewives to buy eggs in the seasons when egg production is plentiful and the price is low, and to preserve them until the times when production falls off and egg prices rise — that is, until a period of the year like this one.

Q — Yes. But what is the method of preserving them?

A — The various theories of egg preservation rest on preventing air from penetrating into the egg through the shell, and on reducing as far as possible the action of microbes within it.

In addition to the familiar method of preservation by low temperature, there are numerous methods, of which we shall mention the easiest to use and the most successful.

Q — Would you, Mr. Shouman, explain these methods to us?

A — The first method is preserving eggs in dry materials, in containers of glass, earthenware, or tin. The dry materials most used for this purpose are very dry bran or sawdust. Put a thin layer of bran in a dry container, then a layer of eggs on top of it, and sprinkle bran over them until the eggs are covered, and so on until the container is full; then place it somewhere away from heat. In this way we can keep them for several weeks.

Q — For several weeks only?

A — If you want to keep eggs for a longer period, replace the bran or sawdust with table salt, which will ensure the eggs keep for about a year. But the salt must be extremely dry when used, and the temperature of the place where they are kept must not exceed ten degrees centigrade.

Q — Thank you... And are there materials other than those you have mentioned for preserving eggs?

A — There is the method of preserving eggs in liquid materials, the most commonly used of which is what is called the lime bath. The containers used in this method are of glass, tin, or cement. Among the advantages of this method are the ease of carrying it out and the cheapness of its cost. It enables us to preserve eggs for several months.

But it leaves a slight taste in the eggs, and an egg preserved by this method must be pricked before it is boiled; moreover, the eggs must be used within ten days of being taken out of storage, and no longer.

Q — And what is this lime-bath method?

A — The lime bath is prepared by dissolving 100 grams of quicklime in a liter of water, mixing it well with a wooden spoon; but before use it is diluted in ten liters of water and left to settle, then strained, only the liquid being taken. The eggs are kept in it in the special containers.

Q — And are there other methods, sir?

A — Yes, there are. A third method is to cover the pores of the shell, after cleaning it well, to prevent air and microbes from seeping inside through the pores. For instance, the eggs may be coated with ordinary liquid Vaseline, coated with it a second time after two days, and left until they are thoroughly dry, care being taken to keep the temperature low. After that they are stored in cardboard boxes or crates, and when the eggs are arranged in rows, a quantity of dry bran is sprinkled between one layer and the next.