<p>The article to determine peculiarities of macromolecule deformation behavior under conditions of a jet-shaping head that would allow to solve the issue related to the mechanism of increasing water-jet cutting power with polymer additions. In converging polyethyleneoxide solution flow macromolecules are forced by a hydrodynamic field to rather strong stretching that causes the dynamic structure formation in solutions. There have been studied experimentally velocity fields and their gradients as well as the degree of macromolecule unrolling under pattern conditions of a jet-shaping head in poluyethyleneoxide solutions flow. In converging polymer solution flow macromolecules are forced by a hydrodynamic field to rather strong (~ 60 % and more) stretching that causes the field restructuring. The determined regularities of macromolecules behavior in the flow under conditions of a jet-shaping head and manifested in this case effects of elastic deformations have paramount importance in understanding the mechanism of «anomalously» high cutting power of water-polymer jet. The work for the first time makes it possible to explain the nature of increased water-jet cutting power with polymer additions when cutting food products. Understanding the nature of increased cutting power of water-polymer jet will make it possible to develop recommendations on choosing regimes for water-polymer jet processing of food products by cutting.</p>

Fracture stress of soybean curd was measured at temperatures between -20 degrees C and -196 degrees C by compression tests. Fracture stress increased as the temperature decreased until it reached a characteristic temperature; below this temperature the fracture stress was constant. Fracture stress varied with the moisture content of the sample measured before freezing; the lower the moisture content, the higher the fracture stress. We attempted to analyze the fracture stress of the frozen soybean curd using a mathematical model in which frozen soybean curd was regarded as a two-component system consisting of pure water ice and concentrated amorphous solution (CAS). Since the volumetric fraction of pure water ice in the system is required for the analysis, the degree of freezing of soybean curd with varied moisture content was estimated as a function of temperature using a hypothetical phase diagram for soybean curd. Based on these data, fracture stress of CAS was calculated using a series model and a parallel model. The calculated fracture stress of CAS was found to be a unique function of temperature and independent of moisture content before freezing.

Aeromonas, like other human enteropathogens, are capable of producing infections at sites outside the gastrointestinal tract and skin, via food or water . The presence of Aeromonas in foodstuffs and in particular the possibility of its growth under refrigerated conditions leads to the conclusion that refrigerated may present potential sources of food borne infection. 24 strains used in our study were from different sources, water, faeces, blood, sweat, row milk, and poultry sausages samples.The most frequent strain A. hydrophila, was found and also A. salmonicida, A. caviae and A. sobria . Refrigerated food may be contaminated with both psychrotrophic and mesophilic pathogens.