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 to normal milk (about 0·71 to 0·73%), the determination of the ash affords valuable assistance to the analyst. When the amount of ash is higher than normal, tests must be made for borax, soda or other mineral matters that are often added as preservatives or acid neutralizers. Borax is easily tested for by dissolving the milk ash in a drop or two of dilute hydrochloric acid, moistening a strip of yellow turmeric paper with the solution and drying it, when, in the presence of even very minute quantities of borax, the yellow colouring matter of the turmeric paper will be changed into a brilliant red-brown. Formaldehyde (which in 40% water solution forms the formalin of commerce) in milk affords a bright purple colour when the milk containing it is mixed with sulphuric acid containing a trace of an iron salt.

Condensed milk is milk that has been evaporated under reduced pressure with or without the addition of sugar. Generally one part of condensed milk corresponds to three parts of the original milk. There is no case on record of adulteration of unsweetened condensed milk, but sweetened milk has in the past been frequently prepared either from machine-skimmed or partly skimmed milk and sold as whole-milk. As sweetened condensed milk is largely used by the poorer part of the population for the feeding of infants, and as the fat of milk is, as stated before, its most valuable constituent, this class of fraud was a particularly mischievous one, and led to the inclusion in the Food Act of 1899 of a special proviso that every tin or other receptacle containing condensed, separated or skimmed milk must bear a conspicuous label showing the nature of the contents. As the bulk of condensed milk consumed in England is imported from abroad, the customs authorities now exercise a strict supervision over the imports, and object to the importation of such condensed milk as contains less than 9% of milk-fat. The average composition of sweetened condensed milk may be taken, with slight variations, to be: water 24·6%, fat 11·4%, casein and albumen 10%, milk-sugar 11·7%, cane-sugar 40·3%, mineral matters 2·0%.

Cream.—There are not any regulations nor official standards relating to this article, the value of which depends upon its contents in fat. Good stiff cream obtained by centrifugal skimming may contain as much as 60% of milk-fat, but generally dairymen’s cream has only about 40%. On the other hand, milk that is abnormally rich in fat is in some places sold as cream. Attempts to compel dairymen to work up to any stated minimum of fat have failed, the English courts holding that cream is not an article that has any standard of quality, but varies with the character of the cows from which the milk is obtained and the food on which they are fed. Therefore, as regards the most important portion of cream, the amount of fat, adulteration does not exist unless there is a substitution for the milk-fat by an emulsified foreign fat, but cases of this description are exceedingly rare. On the other hand, such additions of foreign materials, like starch paste or gelatine, which have for object the giving of an appearance of richness to a naturally poor and dilute article, are not uncommon. While formerly the sale of cream was entirely in the hands of milkmen, there has been of late a tendency to regard cream as an article coming within the range of grocery goods. To enable this perishable article to be kept in a grocery store it has to receive an addition of preservative, as a rule boric preservative, in excessive amount. The purchaser may take it that all cream sold by others than milkmen, and much of that even, is thus preserved and should be shunned. The limit of boric preservative that might be permitted, but which is nearly always exceeded, is one-quarter of 1%.

Butter.—Of all articles of food butter has most fully received the attention of the sophisticator, because it is the most costly of the ordinary articles of diet, and because its composition is so intricate and variable that its analysis presents extraordinary difficulties and its nature exceptional and various opportunities for admixture with foreign substances. It is the intention of the producer of butter to separate the fatty portion of the milk as completely as is practicable from the other constituents of the milk without destroying the fat-globules. This can only be done by churning, by which operation the milk-globules are caused more or less to adhere to each other without losing their individual existence. Owing to this subdivision of the fat, and perhaps to the composition of the fat itself, butter is a more digestible fatty article of food than lard or oil. It is not possible by mechanical means to remove the whole of the water and curd of the milk from the butter; indeed “overworking” the butter with the object of removing the water as completely as possible ruins the structure to such an extent as to make the product unmerchantable. In well-made butter there are contained about 85% of pure milk-fat, from 12 to 13% of water, and 2 or 3% of curd and albumen, milk-sugar or its product of transformation—lactic acid,—and phosphates and other milk-salts. In some kinds of butter, Russian for instance, the percentage of water is rather less. Generally, by churning at a low temperature, a drier, at higher temperatures a wetter, butter is obtained. The curd must be got rid of as completely as practicable if the product is to have reasonable keeping properties. To prevent rapid decomposition salt in various quantities is added. Considering that 100 ℔ (10 gallons) of milk yield only from 3 to 4 ℔ of properly made butter, it is obvious that a great inducement exists to increase the yield either by leaving an undue proportion of water or curd, or by adding an excessive quantity of salt. In some parts of Ireland the butter is worked up with warm brine into so-called pickle butter, whereby it becomes both watered and salted in one operation. Until lately, when the English Board of Agriculture fixed a limit of 16 for the percentage of water that may legitimately be present in butter, this kind of debasement could not easily be dealt with, but even now, where a legal water-limit exists, the addition of water either as such, or in the shape of milk or of condensed milk, is very commonly practised, more or less care being taken not to exceed the legalized limit. It is obvious that there is an ample margin of profit for the mixer who starts with Russian butter containing 10% of water and works it up with milk, fresh or condensed, to 16%, all the other milk-constituents, namely, sugar, curd and salt, thus introduced counting as “butter” in the eyes of the law. A very considerable number of butter-factors in London and in other parts of England thus dilute dry butter and consider this a legitimate operation so long as they keep within the legal water-limit. Nay, they may even exceed this, if only they give to their adulterated article a euphonious name, which, while legally notifying the admixture, raises in the mind of the ignorant purchaser the belief that he is purchasing something particularly choice and excellent. “Milk-blended butter,” with as much as 24 or more per cent of water and as little as 68% of fat, is still largely sold to purchasers who think that they are obtaining extra value for their money; several attempts to deal with the scandal by legislature having led to no result. The introduction of water into butter is also practised on a large scale in the United States, where a branch of trade in “renovated” butter has sprung up. In the States a considerable quantity of butter is produced by small farmers, and by the time the product comes into the market the addition of chemical preservatives to prevent decomposition not being permitted—the butter has so much deteriorated in quality that it fetches a very low price. It is bought up by factors, the fat melted out and washed, then again worked up with water and salt, care being generally taken to leave about 16% of water in the product, which finds a ready sale in England. It may here be pointed out that England imports an enormous quantity of butter from the continent of Europe, the colonies, Siberia and America, the imports, less exports, averaging during 1903–1906 no less than 203,300 tons annually, and the total consumption (home produce plus imports) 366,441 tons, the consumption per head of population being 19·2 ℔ per annum. In butter, as in most other articles of food, adulteration with water is the most common, most profitable, and least risky form of fraud. Great fortunes are thus made out of water.

There is an altogether different class of butter adulteration which concerns itself with the substitution of other fatty matters for the whole or part of the really valuable portion of the