Bacteria


Bacteria -

The family name which includes a great many of the smallest varieties of micro-organisms or "microbes" - minute vegetable growths. They are found in three chief forms - round, rod-shaped and spiral - but as a class they are distinguished by their reproduction by fission - the full grown bacterium, except in a few cases, multiplying by dividing itself instead of producing others by budding (as yeasts) or by seeds or spores (as molds). They are universally recognized as of vegetable nature but some types are motile, the power of movement being often due to hair-like processes called flagella. They are so small that they are discernible only by microscopes of high power - even the width of the finest needle would, compared to a bacterium, look like the width of a man's thumb beside a speck of dust. They are as a class the most important both for good and evil, of all microbes, the most numerous, the most vigorous - and the most difficult to control, for where the conditions are favorable, millions can result within twenty-four hours from a single active specimen left undisturbed. They are present everywhere that life is found, and some of them are always at work in all kinds of moist food unless hermetically sealed or held at the freezing or boiling points. freezing will stop their increase but only heat considerably above the boiling point, or long continued boiling, is a sure destroyer of all kinds.

bacteria are found in great numbers also in various parts of the human body, but under normal conditions the presence there of some types is not only harmless, but absolutely necessary to health and life - for there are, from the human stand-point, both "good" and "bad" bacteria, and we need the former to counteract the latter.

In addition to their functions in the human body - which subject belongs rather in the province of the physician than the layman - and their value in the general economy of the universe - which is too wide a subject for discussion here - bacteria, properly controlled, are of great value in the production of many foods. Their presence in various articles assists digestion by the chemical changes effected and also by producing flavors which stimulate the proper secretion of the digestive fluids which are not excited by flavorless articles of diet.

Some varieties, for example, are almost indispensable adjuncts of butter and cheese making. The "ripening" of cream before churning, is merely waiting for chemical changes to be effected by the growth and increase in it of good bacteria. One thousand million of bacteria to the square inch is a conservative estimate for well ripened cream. butter made from cream too fresh, and therefore deficient in bacterial life, is flavorless. This ripening of cream is not new - though the knowledge of the cause of the change is. Long before the presence and activity of bacteria were discovered, the butter maker used to set his cream aside and allow his unsuspected helpers to ripen it before he commenced churning. Another of the secrets of good butter making is though to know how far to let this change continue, for if overdone the cream is spoiled.

Many bacteriologists have made a study of the production of the best kind of bacteria for the use of butter-makers, and certain varieties can now be procured in open market under the name of "Pure-Cultures." These are used in much the same manner as yeast is used by bakers.

In the manufacture of cheese, bacteria play an even more important part - in fact, its manufacture without them is inconceivable, as the flavors for which cheeses are prized are directly attributable to bacterial agencies - though in some cases, as Brie, Camembert, Gorgonzola, Roquefort and Stilton, credit must also be given to the employment of special "mold" microbes. The production and sale of bacteria for cheese making has reached an active stage in Europe and it is only a question of time when it will be possible to set cultures for all the choicest imported cheeses at work in local American dairies.

Again, the only good table vinegar is the result of the activity of a species of acid-producing bacteria, and even the lactic bacterium, which incurs the enmity of the unthinking by "souring" the milk, is a very good friend - in this particular case the flavor of the milk is spoiled for many people, but the lactic acid formed makes it an especially health-giving drink and prevents for a time other noxious bacteria from rendering it dangerous by decomposition. Indeed, milk that has been "preserved" from souring by checking the formation of lactic acid may prove distinctly dangerous for consumption even though the fresh flavor is retained.

These instances give some idea of the good services rendered under certain conditions by many kinds of bacteria - and they are also indispensable to agriculture and other industries - but in the retailer's establishment and the household they are best regarded as enemies to be fought at every turn, for their uncontrolled access to fresh food is certain to result in loss and sometimes in danger to health. They are far more generally destructive than either wild yeast or molds. All real putrefaction is due to the action of bacteria - the breaking down of the structure of the food as they feed on certain elements in it and other changes caused by their growth and multiplication - and, as already stated, they are present everywhere, being especially plentiful in and around human habitations. Thoroughly dry, salted, smoked and (under certain conditions) spiced and pickled foods are safe from their depredations, but any fresh foods that contain from 25% to 30% moisture, except those that are very acrid or very heavily sugared, offer suitable soil for their growth and multiplication - if undisturbed, they rapidly take them through the various stages of putrefaction to the culminating point of decay.

Daylight, sunshine and cleanliness are opposed to bacteria, so stores and homes, and especially kitchens, should be blessed with all three as a preliminary safeguard. Next, fresh meats, canned goods (after opening) and similar foods should be eaten as fresh as possible. When immediate consumption is impossible, a good refrigerator offers a considerable measure of temporary protection, but it is only temporary, for the growth of some kinds of bacteria is checked by nothing short of freezing.

As already stated, boiling continued for an hour or so after the full heat has permeated every part of the food will kill all kinds of bacteria - will sterilize it - but this must be followed by immediate and hermetical sealing while still boiling hot, or new bacteria may get into it and start propagation afresh.


Arround Bacteria in The Grocer's Encyclopedia


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