10 MASS, EXPERIMENT STATION BULLETIN 437 



He also suggests that 2 percent of the initial cost of the cabinet be allowed for 

 annual repairs, including the replacement of sealing gaskets, refinish of cabinet, 

 or repairs to the refrigerating system. Assuming full depreciation in ten years, 

 he indicated that a reasonable annual allowance for depreciation is 10 percent 

 of the purchase price. Some other authorities have assumed full depreciation in 

 fifteen years. 



Freezing Rate 



In the opinion of most laymen commercial frozen foods are frozen very rapidly. 

 However, even though we speak of them as quick frozen foods, in most cases 

 the freezing time may extend up to several hours, at least. The question is often 

 asked, whether home freezing cabinets can be used for freezing as well as for 

 storage of frozen food. Home freezers do not ordinarily have the capacity to 

 freeze food as quickly as is done in usual commercial practice. Throughout the 

 history of freezing there has been considerable difference of opinion as to the 

 relative merits of "slow" and "fast" freezing. More recently experimental work 

 has demonstrated that in most cases there is but little practical difference be- 

 tween "slow" and "fast" frozen foods if the freezing is completed within 24 hours. 

 Lee and Gortner (10), in studies with peas and snap beans, found no significant 

 difference in quality and nutritive value which could be attributed to the rate of 

 freezing. Their results confirm the results obtained in practice by many home- 

 freezer owners in showing that one need not hesitate to use these facilities for 

 freezing products at home. The authors also stress the importance of speed in 

 handling and cooling foods for freezing and the danger of overloading a home 

 freezing cabinet with unfrozen food. 



Gortner, Erdman and Masterman (7) have summarized the available informa- 

 tion on freezing rate as follows: 



To summarize the best information now at our disposal, it would seem 

 that too much emphasis has been placed in the mind of the public on "quick- 

 freezing" and not enough on "quick to the freezer" and "quick cooling," 

 without which high-quality food is sure to be affected adversely. Without 

 "quick freezing" (a loosely used and much abused term) high quality can 

 still be achieved. With all foodstuffs adaptable to freezing, a rapid freezing 

 rate will prove satisfactory. With most if not all of these foodstuffs, a 

 moderate rate of freezing will prove satisfactory. With a few foodstuffs, 

 particularly when a large cut surface is exposed, a slow freezing rate may 

 prove something less than satisfactory. 



. In appearance, odor, flavor, and nutritive value, the home-frozen product 

 can usually vie with the quick-frozen food in commerce as being a quality 

 item. 



Temperature in Freezing Cabinet Should Not Fluctuate 



If the temperature in the freezing cabinet fluctuates, it can cause a deteriora- 

 tion of the product, particularly if there are some air spaces in the package. 

 When the temperature rises, moisture is pulled out of the food. When the tem- 

 perature drops, this moisture freezes out of the air in the package and is deposited 

 as ice crystals on the surface of the food or the inner surface of the package. 



In a recent publication, Gortner, Fenton, Volz and Gleim (8) have reported 

 the results of a study on the effect of fluctuating storage temperatures on quality 

 of frozen foods. They stored frozen pork, strawberries, green beans, and peas 

 for twelve months at 0°F., at 10°F., and in a freezer alternately fluctuating be- 

 tween 0° and 20°F. in a repeating 6-day cycle. The food stored at temperatures 

 fluctuating between 0° and 20° underwent quality changes similar to those 



