Studies On The Critical Control Points In Yoghurt Production

Milk is one of the ideal foods that can provide full nutrition for humans. However, theyoghourt fermented by the pure microorganisms with the fresh milk is even more beneficial because it can inhibit the growth of harmful bacteria in humans' digestion system. The paper analyzed the factors effecting the quality of the yoghourt on the base of the practical production in Wuhu Weigang dairy Co. Ltd. The total bacteria in raw milk, the content of whole milk solids, the way of thermal processing, the activity of zymogens and fermentation were investigated as the critical control points to optimize the procedure parameters thus producing high quality yoghourt. The results are as follows:1. Discarding the first and second milks, using a washcloth for each cow, cleaning mammilla with disinfectant, storing milk in lower temperature (below 8) immediately after milking and operating mechanical milking manner strictly can control the bacteria number in raw milk under 200 thousand which is in accordance with our national standard.2. Biological and chemical index of raw milk containing trace shuanghuanglian, such as acidity, density, fat and protein content were in normal range with the alcohol experiment negative. Besides, solidification of yoghourt wasn't affected when the content of Shuanghuanglian in milk was up to 1%.3.The yoghourt with best quality could be obtained in the following conditions: whole milk solids content of 11.5%, sterilizing instantly at 120 for 3 seconds, Streptococcus thermophilus and Lactobacillus bugaricus(acidity 87T,aciticy >0.7),incubation content of 3%,cooling instant after fermentation, refrigerating 24 hours at...