Introduction:
For many years in the meat processing industry various types of additives and fat surrogates have been applied. Apart from the primary objective, which is the reduction of fat, they also decrease the contents of cholesterol and calorifi c value, bind water well, due to which they improve the texture of the ready product. The studies conducted were aimed at the examination of the biological purity of fi ne ground sausages of the frankfurter-type, with the addition of eight various additives performing the role of fat surrogates. The numbers of mesophilic microorganisms, yeast, moulds, and souring bacteria of the lactic acid type were determined.

Material and Methods:
Products designed for the study were obtained according to the standard procedure. As a control group, the additive of soy protein hydrolysate, commonly used in production of this type of products, was adopted. The following were applied as the remaining surrogates: oat fl our, buckwheat fl our, corn fl our, potato fl our, fungal chitosan, carob fl our, and durum wheat fl our. Studies of microbiological purity were carried out directly after the process, after 2 and 4-week storage at the temperature of 5°C. Microbiological tests were performed according to the Polish standard: PN-A-82055-1 ‘Meat and meat products. Microbiological examinations’.

Results:
Microbiological purity of the sausages examined for all additives remained within the allowable standard (up to 100).

Conclusions:
In the case of chitosan and buckwheat fl our, the number of microorganisms decreased with prolongation of the period of storage, which is due to the antioxidative properties of the additives examined. Carob fl our also showed a similar property; however, the prolongation of the period of storage to 4 weeks caused a recurrent proliferation of microbes. In the case of the remaining additives, the prolongation of storage time resulted in an increase in the amount of microbes