CHARLES THOM 



439 



or actual continuation of the activities of living cells. The rate of such activity varies 

 greatly, however. Some products such as cereal grains in merchantable condition are 

 comparatively stable, and hence can be handled without special control of conditions; 

 some less stable still admit of shipment, storage, and sale with comparatively simple 

 care; other products truly perishable, such as meats, fresh fruits, and vegetables, are 

 enzymically or metabolically active as well as readily subject to the attack of insects, 

 molds, yeasts, and bacteria. 



The stable products such as cereal grains are commonly grossly contaminated 

 with micro-organisms, but are so low in water content as ordinarily handled that 

 microbic activity is comparatively negligible. Even among these products a slight ad- 

 dition of moisture leads to spoilage as mustiness, moldiness, or souring. 



Among perishable products two general conditions are represented by flesh foods 

 and fresh vegetables or fruits. The flesh foods are high in water content, enzymically 

 active, exceedingly subject to bacterial activity, and usually superficially if not in- 

 ternally contaminated with many types of organisms. In spite of these facts, gross 

 carelessness in handling is constantly observed. Meats — beef, pork, lamb, poultry- 

 are handled in open trucks with little more care than coal or firewood and often ex- 

 posed on hooks, blocks, and counters throughout the business day without protection 

 or icing. Along with the ordinary bacteria of decay or putrefaction which are always 

 present, these foods furnish a favorable substratum for members of the Salmon- 

 ella group whose infective power is so constantly associated with their growth in 

 meat that they are frequently referred to as meat-poisoning organisms. Our pre- 

 cautions against such contamination are commonly inadequate, hence the main pro- 

 tection of the consumer from greatly increased numbers of such outbreaks lies in the 

 adec|uacy of the cooking processes applied. Systematic efforts at the correction of 

 negligence in handling would reduce or stop the introduction into our houses of gross 

 infections carrying the constant peril of contaminations which so frequently escape 

 the precautionary knowledge of those who handle food. 



During the marketing period vegetable products present another problem. Let- 

 tuce, spinach, asparagus, berries, etc, are rapidly growing plants and plant parts. 

 Their growth processes do not stop as the plants are gathered. Bunched in baskets, 

 crates, bags, etc., the heat of metabolism tends to raise the temperature of the mass, 

 and thus to speed up every agency of destruction. Bacteria and molds find warm 

 moist conditions for incubation; the natural enzymes present show increased activity; 

 transpiration furnishes either a highly humid atmosphere in the interstices of the mass 

 or actually wet surfaces in which favorable conditions are offered to micro-organisms. 

 Fabulous numbers of bacteria to the gram develop under such conditions. Spinach, 

 head lettuce, and asparagus become so heavily contaminated with bacteria that they 

 feel slimy to the fingers. Un-iced carloads of such foodstuffs quickly heat, give off 

 steam, and develop offensive odors. Less conspicuous but equally objectionable activ- 

 ities produce the well-known sour flavors of incipient spoilage. 



To handle food safely, therefore, we must take account of the initial load of bac- 

 teria present, product by product, and of the nature of the product itself, as a basis 

 for practical and economical handling. The practice to be selected, product by prod- 

 uct, should be determined largely by the chemical nature of the food mass itself. 



