Breastmilk contains antimicrobial components that fight bacteria. The protective properties of breastmilk have been well established. Please see ‘Why breastmilk?’ for more information on the anti-infective properties of breastmilk.
When breastmilk is heat-treated, bacteria are generally destroyed. Please see ‘How can breastmilk be pasteurized at home?’ and ‘Flash-heating’ for more information on the effect of heat-treating on the biological activity of breastmilk.
Some bacteria form spores when exposed to heat. Bacillus cereus is such a sporeforming 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).
This website writes: “Bacillus food poisoning usually occurs because heat-resistant endospores survive cooking or pasteurization and then germinate and multiply when the food is inadequately refrigerated.” While Bacillus cereus bacterium is easily controlled by proper handling, this bacterium is not reduced by heat-treating. B. Cereus can be of special concern to sick and premature babies because of their compromised immune systems.
Milk banks screen for this and other bacteria before and after pasteurization. Home screening of bacteria is technically possible, but expensive and/or elaborate. Proper handling is important in avoiding contamination of bacteria.
When donating to a premature baby, special considerations may need to be taken into account. Please see ‘What about premature babies?’ for more information and consult with a specialized health care provider when planning on donating to a premature baby.