Storage of Packaged Processed Cheese

The finished, packaged processed cheese should be stored, as far as possible, at temperatures between 5 and 10 °C. Once again it is necessary to emphasized that the processed cheese must not be held at temperatures below 0°C, as freezing can upset its structure. In addition, when the boxes are removed from the cold room,condensation can occur quickly, leading to early spoilage.

When cooling has not been completed, quite often the processed cheese is exposed for a time to temperatures above 20 °C in hot countries as high as 30 °C. This can occur during transport or storage. There is unfortunately a prevailing belief that processed cheese possesses an unlimited keeping quality it often happens that little importance is attached to the storage of processed cheese at higher temperatures.Is processed cheese really absolutely sterile? If a sterilizing process has been used during manufacture, whether by means of a short period ultra high temperature procedure or by means of an autoclave, one can assume that the final product is sterile, so long as a very conscientious and painstakingly clean working operation has been carried out. Unfortunately, the use of a short high temperature processing machine is no guarantee for the production of sterile products. A large number of processing factories still use conventional cookers reaching a temperature between 85 and 95 °C or perhaps slightly higher, so that the possibility of the presence of Clostridia and, in addition, vegetative organisms must always be born into mind.

These organisms, including the Clostridia, will, of course, most certainly continue to multiply and develop with lengthy storage at temperatures around 25-30 °C and eventually cause spoilage and deterioration in the cheese. Therefore, one must avoid storage of processed cheese for long periods at temperatures above 20 °C.Storing sterile processed cheese at higher temperatures is also not advisable because the protein structure and the flavour are detrimentally altered, even though no bacteriological change takes place. In addition, certain defects, which are not evident at normal cold storage, are intensified at temperatures around 30 °C. An example of this is the occurrence of sandiness, which is mostly caused by the formation of fine or course crystals of calcium diphosphate (calcium pyrophosphate). Regular checks are made in most well organized factories by storing representative samples of processed cheese at various temperatures for a certain length of time, e.g., at 10,20,30, and 37°C. From the results obtained after the organoleptic examination of samples stored at 30 and 37 °C, conclusions can be drawn as to possible changes in the products at a later date