121. Molding machinery.—For work on a large scale, special power machines[37] are regularly used. These consist of a hopper and worm delivering a standard size stream of curd through a
Fig. 15.—Neufchâtel and cream cheese molds. proper size and shape of delivery tube. This curd stream is cut by an automatic device into the proper lengths to form the standard cheese. In this way a uniform size of cheeses is obtained. Experimental work with hand apparatus showed that a worm six inches in diameter is required to deliver curd in a smooth column one and one-half inches square. If the pressure is not sufficient, the column will frill at the edges. Such irregular surfaces cannot be wrapped smoothly enough to delay spoilage.
On a small scale, a fair grade of product can be molded through a tin tube (see [Fig. 15]) one and three-quarters inches in diameter and ten inches long in which the curd is compressed by a close fitting plunger operated by hand.
122. Milk for Neufchâtel should be clean, free from gas and taint. Such milk should preferably be not more than twelve hours old when received and in no case show higher than 0.20 per cent lactic acid by titration. Milk testing 4 per cent fat or higher will produce a higher quality of product than lower grade milk, although every grade from skimmed-milk to cream is used in producing some form of Neufchâtel. This milk should be pasteurized unless shown to be free from tuberculosis by proper test of the cattle. Evidence[38] that the organism of tuberculosis will withstand the regular handling process for cheeses of this group and retain its ability to cause disease in experimental animals makes the introduction of pasteurization necessary in this whole group of cheeses. Any effective pasteurization may be used, but temperatures of 140-145° F. for thirty minutes have been effective with less changes in the milk than higher temperatures for shorter periods. The milk should be cooled to curdling temperature and the starter and rennet added and stirred into the milk in bulk. The milk may then be quickly distributed into the curdling cans with a hose or from the gate valve of the mixing vat.
123. Starter.—To insure the development of a clean acid flavor, a small amount of lactic starter should be used. The quantity to use depends on the quality of the milk. With skimmed-milk, a pint for each thirty-pound can is recommended by Matheson and Cammack[39] and by Dahlberg. (See page [98].) For whole-milk Neufchâtel, 2 c.c. to a thirty-pound can of milk commonly gives good results. On this basis 2 ounces of starter would be sufficient if properly stirred into about 1000 pounds of milk. Too slow development of acid is preferable to over-rapid souring.
124. Renneting or setting.—The milk should be cooled after pasteurizing to between 70° and 75° F. Rennet is added at the rate of ½ c.c. to a thirty-pound can (roughly ⅓ ounce to 1000 pounds). This will thicken the milk sufficiently in the first few hours to reduce the separation of the cream. For completion of the curdling and souring process, twelve to eighteen hours are required. Usually the cans stand overnight at uniform temperature. When ready to drain, the curd should be firm, smooth and mildly acid. Whey separating from it should not titrate above 0.35 per cent titrated as lactic acid.
125. Draining.—A cloth is spread over a draining rack and the contents of one "shot-gun" can poured upon the cloth with as little breaking as possible. In this way a large surface is exposed. The room must be kept wet to prevent the surface of the curd drying to form crusts which stop draining. A temperature of 60° F. is favorable to the maintenance of proper texture and humidity without the development of objectionable organisms, especially Oidium lactis, which tends to cover every exposed surface in such rooms. Draining may be hastened by turning the curd or changing the position of the cloth. In factory practice, the large draining surface reduces the necessity of handling the curd and reduces the loss of fat. About twelve hours are required upon the draining racks.
On a small scale with a few cans of curd in the home, any form of draining rack may be used, such as a potato or berry crate, or the corners of the cloth may be brought together, tied and the mass hung up. The curd must be turned by pulling up the corners of the cloth to prevent drying at the edges and stoppage of draining from the center of the mass. Such treatment produces much more rapid drainage than the factory practice and involves proportionately more labor and larger fat losses.
126. Cooling Neufchâtel.—When whey ceases to separate readily, the corners of the cloth are loosed from the rack, folded diagonally or tied, and the curd cooled on ice or in refrigerators. When thoroughly chilled the bags of curd are put into presses, where light but increasing pressure forces more whey out of the mass. Tests at this time should show about 0.60 per cent acid in the whey. With low-fat curd every step of the process may be hastened, but with high-fat care must be exercised to prevent loss of fat during pressing especially. Any pressing device permitting continuous pressure with ease of manipulation may be used.