ELLENBERGER. Study of Bacteria in Ice Cream during Storage. Cornell University Agricultural Experiment Station Memoir 18, pages 331-362 (1919). HAMMAR and SANDERS. A Bacteriological Study of the Method of Pasteurizing and Homogenizing the Ice Cream Mix. Iowa Agricultural Experiment Station, Bulletin 186 (1919). REDFIELD. Remade Milk and Cream. 32 pages. Published by International Association of Dairy and Milk Inspectors, May, 1919. CROSS. Standardizing Calculations of Ice Cream Mix. Creamery and Milk Plant Monthly, Vol. 9, No. 11, pages 50-53 (1920). WASHBURN. What is a Fair Standard for Ice Cream? Journal of Dairy Science, Vol. 4, pages 231-239 (1921). ZOLLER. Rotating Thermocouple and Cold Junction for Temperature Studies in Commercial Ice Cream Machines. Ice Cream Trade Journal, Vol. 17, No. 8, pages 40-43 (1921). Separation of Ice in Freezing Ice Cream. Ice Cream Trade Journal, Vol. 17, No. 9, pages 45-47; No. 10, pages 50-52 (1921). BABCOCK. The Whipping Quality of Cream. United States Department of Agriculture, Bulletin 1075 (1922). WILLIAMS. Proportioning the Ingredients for Ice Cream and Other Frozen Products by the Balance Method. United States Department of Agriculture, Bulletin 1123 (1922). HARTSON. Some Facts about Powdered Milk. The American Food Journal, Vol. 18, pages 368–369 (1923). TRACY. A Study of the Use of Superheated and Unsuperheated Plain Condensed Bulk Skim Milk in the Manufacture of Ice Cream. Journal of Dairy Science, Vol. 6, pages 205-221 (1923). WILLIAMS and CAMPBELL. Effect of Composition on the Palatability of Ice Cream. United States Department of Agriculture, Department Bulletin No. 1161 (1923). SMITH. Vitamins in Ice Cream. Journal of the American Medical Association, Vol. 79, pages 2221-2222 (1922). CHAPTER V EGGS DOUBTLESS eggs of various kinds were among the very earliest of human foods. At the present time only the eggs of hens, ducks, geese, guinea fowl, and turkeys are commonly used for food; and of these, hens' eggs are so much more abundant than all others that, unless otherwise explained, all statements made here may be understood as referring to hens' eggs. Production The production of eggs is widely distributed. It is estimated that about nine tenths of all farms in the United States keep chickens and produce eggs. It will be seen from Fig. 9 that in poultry culture there is less tendency toward concentration in particular regions than is the case with many other food industries. It is difficult to measure the egg production of the country, because eggs are so largely consumed by the producer or sold at retail without going through trade channels from which accurate statistics can be obtained. The United States Census Bureau estimates the egg industry at seventeen and one half dozen eggs per capita per year, i.e. an average of 210 eggs per year or 4 eggs per week for each person in the United States. Pennington and Pierce, writing in 1910,1 reported that only the states of Ohio, Indiana, Illinois, Iowa, Minnesota, Nebraska, Kansas, Missouri, Texas, Tennessee, and Kentucky produce more eggs than are consumed within their own borders, and this 1 United States Department of Agriculture, Yearbook for 1910. FIG. 9. Distribution of chickens in the United States according to the census of 1900. Reproduced by permission from surplus production does not continue throughout the year, but only during those months which are most favorable to laying. From Tennessee and Kentucky most eggs are sent to market during the period from December to April; from southern Ohio, southern Kansas, Missouri, and Texas many eggs are shipped during March and April; in the later spring northern Kansas, Iowa, Illinois, and the Central States generally show their heaviest production, while for Michigan and Minnesota the season is still later. For the country as a whole as judged by the data of the large markets, the months of March, April, May, and June are those in which the largest number of eggs are shipped by the producers. During these months many eggs are placed in cold storage to be sold later when the supply is less abundant and the price higher. Eggs are graded in the market chiefly according to freshness, cleanliness, size, cracks, and color. Freshness in this connection means the firmness and state of preservation of the egg rather than the mere length of time since laying. This freshness is determined chiefly by the process known as candling, which consists in looking through the egg against a bright light, such as an incandescent electric light, surrounded by an opaque shield in which is a hole shaped like an egg but slightly smaller in size. The egg is pressed firmly against this hole, and as the light shines through it, the white and the air-chamber may be observed. Figure 10 shows the appearance of a fresh, sound egg and of eggs which have undergone different types of deterioration. Eggs sufficiently sound to pass the candling test may still be subdivided into many grades according to age, color, size, and cleanliness. It is these qualities rather than chemical composition and nutritive value which determine the very different prices at which eggs are sold in the same market and at the same time. |