Research on the appreciation of the hygienic status of the raw milk using the dosage of the catalase activity

Abstract

Research conducted in recent years on the hygienic quality of milk, using the main indicators determined the existence of quality grids that were used and in the present paper helping to classify milk samples to different quality classes. Through this paper we tried to use the main rapid enzymatic tests to assess the freshness and hygiene of the raw material milk, depending on its retention time and any contamination with alterative microflora at the shelter / milking level, 25 samples of fresh milk, stored for 5 days under refrigeration conditions and experimentally contaminated milk were obtained by haemorrhage. The determinations consisted in highlighting the acidity (°T), carrying out enzymatic tests catalase and reductase, identifying the number of somatic cells and the total number of germs. Regarding the catalase test, it revealed a reduced microbial load in the fresh milk, indicating that it can be processed industrially or consumed after thermal processing. The milk refrigerated for 5 days and the experimentally contaminated milk presented medium and high microbial contamination, according to the catalase test, being risky, respectively unfit for consumption. Regarding the test of reductase, it included the samples of fresh milk in class I of quality (lack of risks, immediate use after thermal processing); those of refrigerated milk in the second class of quality (exclusive use after industrial processing); those contaminated experimentally in quality class III (confiscation and prohibited use for food purposes). As a final conclusion, he stated that enzymatic tests to identify catalase and reductase can be successfully used to determine the degree of contamination of milk and to determine its hygienic quality, the results of which are correlated with the total number of germs and with the titrable acidity.