| Congresso Brasileiro de Microbiologia 2023 | Resumo: 188-1 | ||||
Resumo:The World Health Organization (WHO) has prioritized the development of guidelines to establish and implement safe and quality human milk banking systems. Brazilian legislation establishes that pasteurized human milk, once thawed, must be kept under refrigeration at a maximum temperature of 5 °C, with a shelf life of twenty-four hours. In this context, knowledge of the growth potential (δ) of pathogenic bacteria in human milk can be useful to identify critical storage conditions to be respected to guarantee the safety of the milk distributed by the human milk bank. This study aimed to evaluate the growth potential of four pathogenic bacteria in raw and pasteurized human milk stored at 5 and 10 °C. Three strains of Staphylococcus aureus, two of Escherichia coli, one of Salmonella, and five of Listeria monocytogenes were used. An inoculum was prepared for each bacteria, which was individually inoculated into 10 mL samples of pasteurized and raw milk and incubated at 5 and 10 °C, with the enumeration of the bacteria carried out at 0, 12, 24, 48, and 72 hours after incubation. The growth potential (δ) is the difference between the population (log cfu/mL of milk) after growth and the initial concentration of the bacteria. If δ is higher than 0.5 log cfu/mL, then it is assumed that human milk is able to support the growth of pathogenic bacteria; otherwise, human milk is incapable of supporting the growth of bacteria. The growth potential was distinct among the bacteria studied; S. aureus did not show significant potential for multiplication over the storage time for any evaluated experimental condition, pasteurized or raw milk, and storage temperatures of 5 and 10 °C. E. coli, on the other hand, showed a significant growth potential (δ) only for raw milk stored under temperature abuse (10 °C) after 72 hours. Unlike S. aureus and E. coli, Salmonella, and L. monocytogenes showed significant potential (δ) only for pasteurized milk stored under temperature abuse conditions (10 °C), after 48 hours for Salmonella and 72 hours for Listeria. The storage temperature of pasteurized human milk in the distribution for consumption seems to be a more relevant critical point than the storage time to guarantee the safety of this milk. There is a trend toward a reduction in the population of bacteria at all times evaluated for milk stored at 5 °C. The growth of E. coli, L. monocytogenes, Salmonella and S. aureus in pasteurized human milk can be controlled for up to three days by ensuring the milk is stored at temperatures below 5°C. Palavras-chave: Salmonella, human milk bank, Listeria monocytogenes, Staphylococcus aureus, food safety | |||||