Ropiness of bread is fairly common in home baked bread, especially during hot weather, but it is rare in commercially baked bread because of preventive measures now employed. Ropiness is caused by Bacillus subtilis , B. panis and other species. The spores of these species can withstand the temperature of the bread during baling, which does not exceed 100 C and can germinate and grow in the loaf if conditions are favorable.
Another type of spoilage of bread is chalky bread which is caused by growth of yeast like fungi Endomycosis fibuligera and Trichosporon variable.This spoilage is characterized by development of white chalk like spots.
An unusual spoilage of bread is Red or Bloody bread, which is due to the growth of bacteria Serratia marcescens.This organism produces brilliant red color on starchy foods giving blood like appearance. Neurospora and Geotrichum may also be involved in imparting pigmentation during spoilage of bread.
Ropiness of Bread
A large number of products available at retail are essentially prepared, refrigerated, or frozen bakery product doughs. These items may contain yeast or lactic acid bacteria inoculums. The level of contamination and the subsequent microbial quality would be a direct result of the quality of ingredients used and the sanitary practices employed during their manufacture.
Pasta and Macaroni
Pasta here is used to describe egg based pasta usually containing flour, water and eggs. Pasta is delivered and stored dry, therefore there are seldom reports of spoilage in these products. Swelling of moist macaroni or pasta can take place caused by gas production by bacterial resembling Enterobacter cloacae. During the drying of macaroni on paper a mold of the genus Monilia has been found responsible for purple streaks at contact points with paper. The appearance of these defects is uncommon however despite the long slow drying process of macaroni.
Cakes and Bakery products
Molds are the chief cause of the microbial spoilage of cakes and other bakers products, since the normal baking process destroys much of the original microflora. Usually toppings or fillings are more prone to microbial spoilage than is the actual baked portion. It is not unusual for the fillings of many pastries to support the growth of microorganisms. Frosting because of their high sugar content are quite stable but may be spoiled by molds or yeast upon storage.