A dealer who will accept adulterated milk when he can protect himself at such a small expenditure of time and money, deserves no sympathy when brought before a jury. Tables No. 1 and 2 which follow will enable the dealer to calculate the solids not fat very closely. The milk must be thoroughly mixed just before beginning the test. Before determining the per cent of fat in the milk, the lactometer reading is taken, the temperature of the milk being determined at the same time. Then by means of Table No. 1, the lactometer reading at 60°F is found. If the fat is found to be 3.4 per cent and the hydrometer reading is thirty-two at the temperature 70°F, we proceed as follows: Find in the left hand column of Table No. 1 the temperature of the milk, then follow the line horizontally to the right until the column is reached under the lactometer reading. The figure there found is the lactometer reading at 60°F. In the above case this is 33.4. To find the solids not fat: Find in the left hand column of Table No. 2 the per cent of fat in the milk, then follow the line horizontally to the right until the column is reached under the lactometer reading at 60°F (the fractional part 0.4 being set aside.) In the above case this is found to be 8.94. The fractional digit must be multiplied by 0.025 and added to the number found in the above table. In the case taken this would be 0.025 times 4 equal 0.1, which added to 8.94 gives 9.04, the per cent solids not fat. PRESERVATIVES IN MILK. The use of preservatives in milk is in direct violation of the law, and very few milk dealers in the State used them this past year. This may be due to several causes. (1st) Many milk dealers have been convicted and fined during the past two years for the use of preservatives. (2nd) It is now against the State law to sell or offer for sale any compound or mixture intended for use as a preservative of milk or cream, and thus it is more difficult for the dairymen to procure the chemicals. No matter what the cause, it is very gratifying to see that the use of preservatives in this State has so nearly ceased, for it is a certain fact that the use of milk containing these harmful chemicals is especially dangerous to infants and invalids. For this reason the commission has been very active in suppressing the practice of artificially preserving milk. In 1906 there were thirty-four samples of milk analyzed which contained formaldehyde. In 1907 only five cases were found, and in 1908 only two. The ordinary preservatives used contain formaldehyde, borax or boracic acid. These preservatives are easily detected. In the test for formaldehyde, about 15 cc of milk is placed in a test tube with an equal aomunt of strong hydrochloric acid and a drop of ferric chloride. This mixture is gently heated and if formaldehyde is present a purple coloration is produced. Those having a Babcock machine may make the test for formaldehyde at the same time they test for. fat. If a few drops of iron chloride are added to the sulphuric acid used for testing milk a pur ple coloration will be produced in the Babcock milk bottle in the milk at its juncture with the sulphuric acid, after standing two or three minutes, in case formaldehyde is present in the milk. To test for borax or boracic acid, the milk is made alkaline with barium hydroxide and after evaporating to dryness is burned to an ash. The ash is boiled with a little water and made acid with hydrochloric acid and a strip of turmeric-paper dipped in the mixture. If the borax or boracic acid is present the strip of paper turns pink in the drying. CAUTION. Milk dealers sometimes use washing powders which contain these preservatives to clean their cans. Unless the can is well rinsed with hot water after the use of these mixtures, some of the preservative may find its way into the milk and thus make the dealer liable to prosecution. ANALYSES. During the past year 1,018 samples of milk were examined in this laboratory. Of these 218 were illegal, generally due to adulteration with water or by skimming. CITY BOARDS OF HEALTH NOT ACTIVE. This suggests that the boards of health in our cities are in many cases not actively fighting this form of adulteration. During the past two years several boards of health have visited this laboratory to receive assistance as to methods of testing milk. Every assistance in our power has been given them. The tables and other information given under the heading, "The milk dealer can protect his customers" together with the other parts of this report, will, it is hoped, present the matter as being simple enough to arouse the interest of many boards of health who have heretofore not been active in the milk crusade. |