Influence of storage and heating on mother´s milk microbiota

Abstract

BACKGROUND: There is a consensus among many authors that the newborn (NB) is particularly prone to infections of the gastrointestinal tract for multiple factors, such as the hypoxia and the artificial milk. These factors facilitate the abnormal bacterial colonization and promote a drawback in the destruction of the toxins of such bacterias. AIM: To identify the microorganisms in the breast milk, after its storage in the refrigerator at 4°C, as well as after heating and to relate the eventual clinical NB signs with the microbiologic laboratory results of the breast milk which was offered. METHODS: The samples collected contemplated the three phases of post-natal breast milk. In 16 cases, the colostrum type was obtained as yellowish milky secretion, up to the beginning of the second week after the birth. In 14 cases, the transition type was obtained as intermediate product of the mother's milk, between colostrum and the mature milk, between the 7th and the 15th day after the birth. In 14 cases, the mature type was obtained as a white opaque liquid, of light smell and sweet taste, from the 15th day after birth. The milk types obtained in the three presentations were subdivided according to the period of conservation and heating in the group colostrums, transition and mature. RESULTS: The microorganisms which did not present growth were: Salmonella sp, Molds/leavens and Pseudomonas aeruginosa. The total coliforms and fecal coliforms were observed. There was no significant microorganisms growth. The aerobic mesophiles, Staphilococcus aureus and Bacillus cereus were also observed. These microorganisms presented growth, but the NBs did not present damage in their clinical status. CONCLUSIONS: Under this conditions of collecting and storage, there was no fecal coliforms, Salmonella sp, Molds/leavens and Pseudomonas aeruginosa; the microorganisms which grew up, kept themselves above the limits of detection (aerobic mesophiles, total coliforms, Stapholococcus aureus and Bacillus cereus; microbian rates, even when higher than the ones stablished, did not influence the clinical status of the NB; the breast milk collected, transported and stored under the conditions presented in this study can be safely used up to 24 hours after being stored in a refrigerator at 4°C.