ANIMAL PRODUCTS 



259 



They may, therefore, become moldy and 

 lose their flavor. Moreover, if natural 

 ice is used, there is danger of contami- 

 nation from disease germs and other bac- 



Fig. 187 — SCALDING THE HOG 



teria, for it must be remembered that 

 bacteria do not lose their virulence by 

 freezing. 



Investigations by the German Impe- 

 rial Health Office and the Massachusetts 

 State Board of Health have shown con- 

 clusively that ice, even when of the best 

 appearance, often contains numerous 

 disease germs still virulent and quite 

 capable of development. The require- 

 ments of hygiene are better served when 

 a device is used by which the ice does 

 not come in immediate contact with the 

 food products to be preserved, but is 

 separated from them by a division wall. 

 In the ordinary household, both methods 

 are in daily use, but the second method 

 is far preferable. Food products are 

 thereby cooled indirectly by cold air and 

 are protected against the moisture and 

 possible contamination from natural 

 melting ice. In such devices the ice is 

 placed between double walls in the side 

 of the cooling room, in the middle, or 

 on the ceiling. 



Numerous small refrigerating plants 

 of this sort are in operation. Typically, 

 they consist of three rooms — ice room, 

 cooling room and antechamber. The 

 second and third connect by means of a 

 door, while the first and second are sep- 



arated by a division wall. The ice room 

 should be higher than the refrigerating 

 room and cold air passes into the latter 

 through slits which may be opened or 

 closed as desired. The cold air descends 

 to the floor, removing the heat from the 

 hanging meat or other products, after 

 which it rises and passes through a ven- 

 tilator in the ceiling. When properly 

 constructed, such plants may be quite 

 satisfactory and the meat as well as the 

 inner walls may remain dry. The busi- 

 ness should be so arranged that the cool- 

 ing room need not be opened more than 

 twice daily. 



In such plants meat may be kept suc- 

 cessfully for several weeks, and they pos- 

 sess the advantage of simplicity and 

 cheapness. The Brainard system was 

 devised to secure dry air in the cooling 

 room. According to this system the ice 

 is stacked on a corrugated metal sheet 

 over the cooling room. The metal sheet 

 furnishes a large surface on which the 



Fig 188 SPLITTING DOWN THE HOG 



moisture may be condensed and con- 

 ducted away in grooves. As shown by 

 Ostertag, however, cold storage houses 

 which use natural ice cannot compare in 



