Holder pasteurization and flash-pasteurizing both inactivate viruses such as HIV, HTLV, HTLV, HBV, HCV, CMV, and bacteria. Each process has a different effect on the anti-infective properties and biologically active components of human milk.

Flash-heating has been shown to deactivate HIV and 4 bacteria while retaining most anti-infective properties, but further research is needed to assess the effect on other pathogens.

It is important to note that some bacteria form spores when exposed to heat. Bacillus cereus is such a spore-forming bacterium and has been known to cause about 2% of the total cases of food poisoning. It is widely found in nature (soil, crops, water). For more information please see Bacteria.

See this How can breastmilk be pasteurized at home? for more information.