Analysis of psychrotrophics and proteolytic psychrotrophics in integral yoghurt

Abstract

Whole yogurt is a very consumed food in Brazil, but like any dairy derivative, susceptible to contamination. The objetive of the work was to detect the presence of psychrotrophic and proteolytic psychrotrophic bacterium in whole yoghurt, since these are bacterium indicative of their microbiological quality. The results found were not satisfactory for the psychrotrophic count, because although Brazilian legislation does not stipulate maximum limits for these microorganisms, their presence is undesirable because they cause economic losses, among other problems. Four analyzes were carried out during the period of validity of the yogurt, where the first sample (day 0) had a count of 8.0x102, the second one (day 7) had a reduction of 50%, (4.0x102) The third sample (day 21), 0.5x102 and the last analysis was negative. In order to count proteolytic psychrotrophics, there was no detection of viable microorganisms, but despite this, their enzymes can act on the yogurt components causing changes, which was not evaluated in the present research. It is concluded that despite efforts to maintain quality, there are still shortcomings in the manufacturing process, stressing the need to control the production stages of yogurt and obtaining a milk with good quality, since this is the main raw material in the production of yogurt.