Abstract:
Milk and milk products are an important as they gain demand because of its
nutritional and organoleptic properties. Milk is perfect medium for microorganism to
grow that favours it’s resulting in subsequent spoilage. Thus, bacteria can easily be
attracted and can rapidly multiply. Hence, in milk industry milk processing plays a
major role leading to the enhancement of keeping quality of milk.
The microbial count of 1ml of raw milk is normally uncountable. Heat
processing is done to bring this count to a lower safer level. Sterilized milk bottles
shelf life is about 5 months. Normally commercial sterilization, spores are present 1
bottle out of 100. If milk bottles retain, bacteria it leads to the curdling of bottles.
They may be post contaminated or process operation problem may retain bacteria
spores in sterilized bottled.
Curdled bottles were taken and identified the presence of bacteria by using
culture techniques. After that gram staiftmg. test was done for differentiation of
bacteria either gram negative or gram positive. Degree of contamination was
determined by drawing sample from all stages in process line and through following
enumeration of TCC, Td and Tp bacteria. Sterilized bottles were incubated various
temperature and identified the optimum temperature for curdling of bottes.55-60 °C
range is considered to this most suitable temperature.
Changing of the pH acidity in curdles bottles reflects presence of bacteria in
bottles. This variation was identified by measuring the pH and acidity in curdle and
normal bottles.
The bottles may contaminated by remaining spores if washing process is
inefficient. Therefore, the strength of washing tanks (pre soak and main soak) has
been calculated. These calculations were done every testing day. After washing the
remaining causticities were identified by adding the drop of phenolphthalein.
Samples were collected to be determining the process temperature variability
this was done 3 times per day. The Changing in bottle sterilization method using
autoclave lead to the poor time- temperature combination exposure to all the sterilized
bottles. After the incubation at 55°C period, autoclave sterilized bottles were not
curdle that identified. The heat treatment of milk causes some changes in the
properties of mi lk depending upon the time temperature combination.
