Hi,

I think that this bactofugation process was initially meant to improve the shelf-life of pasteurised milk, i.e. milk that is treated at relatively low temperatures (60-70 °C) to kill pathogenic bacteria, with little effect on thermophilic bacteria and no effect at all on spores.

In the case of UHT (Ultra High Temperature) treatment, milk is actually sterilized applying much higher temperatures (130-150 °C) in a way that both bacteria and spores are inactivated, not only the pathogenic ones. In this case, the shelf-life, is already much longer than pasteurized milk (months instead of days). Usually spoilage in UHT milk is due to heat resistant proteases or to the destabilisation of milk constituents, rather than to vegetative forms of bacteria.

For such reasons, I think that pre-processing milk with bactofugation before the UHT treatment could only give a slight (if any) improvement of its shelf-life.

However, no need to say, the raw material is always important. I don't know what could be the interest for a hardly contaminated raw milk. But there again, I tend to think that a milk that is heavily contaminated with bacteria may have other problems that could not be solved with bactofugation, such as possible polluting toxins and modification of pH, proteolysis, lipolysis etc...

This is my opinion, at least, I'd be curious to read others' view on this subject.

I totally agree with the opinion of Leonardo.

Bactofugation of milk as a pretreatment can reduce the number of bacteria spores (actually by 99% appr.) but the UHT treatment itself results almost or totally sterile product. At last, the chance of the reinfection of UHT milk in an aseptic processing line is not to likely.  

But, of course, the original quality (icluding the microbiological quality) of raw milk determines the quality of products, also due to other point of views.So, we have to keep the number of spore form bacteria (and all bacteria) in raw milk at a very low level (remember the requirements of milk for cheese making), because the killing of them needs extreme condition.. like UHT. But the high temperature causes disadvantageous changes in milk......  

Bactofugation prior to UHT processing of milk will improve the shelf life of UHT milk and help in controlling the defect like age gelation, which is caused by proteases secreted by surviving bacillus spores.

I'm going to answer this tentatively. I have never used bactofugation in UHT, however a while ago I looked into it. What I read was that bactofugation can reduce spore count by 99% (in the cheese industry anyway) somatic cells, which will reduce the occurrence of proteases . This may allow you reduce your UHT processing temperature. The pre treatment process is a key step in reducing plasmin so this temperature must not be altered.