Practical Sanitary Science (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...of butter aie characteristic, and excellent tests of its purity. By heating it to 250 C. any unpleasant taste that it may possess becomes more apparent. Adulteration.--Foreign fats are the chief item of adulteration. Colouring matters, especially annato, are frequently employed. Water is sometimes worked into butter for the purpose of increasing its weight; but, as the addition of water renders butter liable to decomposition, it is only possible to escape detection in cases where Beaker for melting Bottle beaker with funnel Graduated test-tube Platinum crude butter. for tiltering butter-fat. for Valenta test. basio. Fig. 23. the butter is rapidly disposed of. The addition of pepsin, rennet, etc., to milk before churning aims at increasing the yield of butter by securing an increase of contained water. The Estimation of Water.--At present butter is allowed to contain 16 per cent, of water. The following two methods readily determine the amount of water; the second is the more accurate. 1. Weigh out 10 grammes of butter into a small platinum or porcelain basin provided with a piece of glass rod which acts as a stirrer. Heat on a sand bath or over a small flame, and carefully stir until all frothing ceases. It is necessary to regulate the temperature so that the curd is not appreciably browned during the heating, and that there is no loss by spirting. The basin with its contents is cooled in a desiccator and weighed. The loss of weight represents the water in 10 grammes. 2. Fill a small platinum or porcelain basin with pieces of pumice that have been recently washed and ignited. Select portions of butter from three different regions of the sample (water is not always equally distributed throughout the mass of butter), and place them in a clean, wide-mouthed, s...