476 MICROBIOLOGY OF SPECIAL INDUSTRIES 



microorganisms prevented. Unquestionably there is a marked differ- 

 ence between the ordinary cold-storage egg and the strictly fresh egg, 

 but to what extent this deterioration may be due to errors in storage, 

 such as inaccurate control of temperature and humidity, use of odorif- 

 erous crates for packing, decomposition changes previous to storage, 

 too rapid chilling of the eggs, or too rapid warming of them after 

 removal from storage, and to what extent it is inherent in the most 

 perfect cold-storage procedure, is still somewhat uncertain. Doubt- 

 less a certain amount of deterioration, especially the loss of the pecuhar 

 flavor of the fresh egg, is unavoidable in any method of prolonged 

 storage. The discrimination in price in favor of new-laid eggs in the 

 market is an indication of difference in actual value, and the sale of 

 cold-storage eggs for new-laid or strictly fresh eggs is generally recog- 

 nized as a fraud by the purchaser and doubtless will in time be so 

 recognized by law. The cold-storage egg is nevertheless a very valuable 

 food and the economic importance of saving the over-abundant supply 

 produced during the spring for use during the colder season of the year 

 makes this industry a great benefaction to the public. Suitable regula- 

 tion may be expected to remove its objectionable .features. 



Milk and Butter. — Milk as ordinarily sold at retail is not subject 

 to sufficient seasonal change in market price to make its prolonged 

 storage advisable. But milk is so rapidly changed by bacterial activity 

 at ordinary temperatures that efficient dairy methods necessarily in- 

 clude prompt cooling of the milk after it is drawn from the animal 

 and the maintenance of a low temperature until it is delivered to the 

 consumer. At the low temperature bacteria slowly multiply, unless 

 the milk is actually frozen, but at a temperature slightly above the 

 freezing-point very clean milk may be kept in perfect condition for a 

 week, and it may be kept sweet for several weeks. Refrigeration of 

 milk cannot compensate for unhealthy animals producing it, nor for 

 careless and uncleanly methods of handling. The cold does not 

 destroy the microbes in the milk but only retards their multiplication 

 and chemical activity. In practice, especially in the transportation of 

 milk into large cities, it is frequently most economical to freeze the milk 

 and trust to insulation and the latent cold in the ice to maintain a low 

 temperature during transportation. Such milk should arrive at its 

 destination in a partly frozen condition. 



The cold storage of butter is essential even when it is kept for only 



