RHEOLOGICAL CHANGES IN IRRADIATED CHICKEN EGGS

Pathogenic bacteria may cause foodborne illnesses. Humans may introduc e pathogens into foods during production, processing, distribution and or preparation. Some of these microorganisms are able to survive conv entional preservation treatments. Heat pasteurization, which is a well established and satisfactory means of decontamination/disinfection of Liquid foods, cannot efficiently achieve a similar objective for soli d foods. Extensive work carried out worldwide has shown that irradiati on is efficient in eradicating foodborne pathogens like Salmonella spp . that can contaminate poultry products. In this work Co-60 gamma irra diation was applied to samples of industrial powder white, yolk and wh ole egg at doses between 0 and 25 kGy. Samples were rehydrated and the viscosity measured in a Brookfield viscosimeter, model DV III at 5, 1 5 and 25 degrees C. The rheological behaviour among the various kinds of samples were markedly different. Irradiation with doses up to 5 kGy , known to reduced bacterial contamination to non-detectable levels, s howed almost no variation of viscosity of irradiated egg white samples . On the other hand, whole or yolk egg samples showed some changes in rheological properties depending on the dose level, showing the predom inance of whether polimerization or degradation as a result of the irr adiation. Additionally, irradiation of yolk egg powder reduced yolk co lor as a function of the irradiation exposure implemented. The importa nce of these results are dicussed in terms of possible industrial appl ications.