252 BIOLOGICAL ACTIVITIES OF MOLDS 



Molds cause considerable trouble in the meat-packing industry, 

 particularly with the various kinds of preserved meats. The growth 

 of molds on hams, sausages, and bacon is very superficial and causes 

 no pronounced decomposition of the product, but does cause marked 

 economic loss through the expense of "reconditioning" the product 

 and the reduced value due to its altered appearance. Molds and 

 yeasts usually multiply extensively in the pickling vats. They 

 are considered desirable by some packers, as they are supposed to 

 take part in the chemistry of the pickling process and produce 

 desirable flavors. However, others consider them undesirable. 



The occurrence of molds on meat products appears to be largely 

 determined by the degree of handling and the humidity of the stor- 

 age rooms. Lewis and Yesair^'^ isolated the following species from 

 various meats, pickling solutions, and the walls or containers of the 

 packing plants: Mucor racemosus, Rhizopus nigricans, a species of 

 Mortierella, "Oidium lactis," Neurospora sitophila, Monascus pur- 

 pureus, "Aspergillus glaucus," A. niger, A. clavatus, Penicillium ex- 

 pansum, Alternaria tenuis-, and a species of Fusarium. These were 

 studied with regard to their temperature relations, their ability to 

 adhere to and stain sausages, and the effects of various humidities, 

 as well as their resistance to sodium hypochlorite and ozone. Jen- 

 sen ^° is ■ of the opinion that the enzymatic activity displayed by 

 molds should be included in the list of causes of fat spoilage. He 

 has surveyed the literature for reports of the various microorganisms 

 which have been found to possess lipolytic activity. In his Micro- 

 biology of Meats, he has also discussed the organisms found in vari- 

 ous meat products. 



Of the various dairy products, butter is most subject to mold 

 spoilage, although Geotrichum candidum and Scopulariopsis brevi- 

 caulis are frequently causes of undesirable flavors in cheese. Moldi- 

 ness in butter is largely dependent on the initial contamination of 

 raw materials, on manufacturing procedures, and on the temperature 

 of holding. Macy and Combs ^* found the sources of contamination 

 (in order of descending frequency) to be the raw cream (which was 

 always contaminated), dry parchment, piping and pumps of the 

 ' creamery, water, starter cultures, and salt. Thom and Shaw ^^ recog- 

 nize three main types of moldiness, the smudged type with dark or 

 smoky areas due mainly to species of Alternaria and Cladosporium; 

 the green type, due to PenicilUa; and the "Oidium" type, with 

 patches of yellow or orange discoloration caused by G. candidum. 

 A consideration of mold spoilage of stored fruits and vegetables 

 carries one into the domain of plant pathology, for some of the rots 



