Objectives: The objectives of the present study were to enumerate and characterize the pathogenic potential of the Bacillus population that may survive holder pasteurisation of human milk and to evaluate the nutritional damage of this treatment using the furosine and lactulose indexes.
Materials and Methods: Milk samples from 21 donors were heated at 62.5°C for 30 minutes. Bacterial counts, lactose, glucose, myoinositol, lactulose, and furosine were determined before and after the heat treatment. Some B cereus isolates that survived after pasteurisation were evaluated for toxigenic potential.
Results: Nonpasteurised milk samples showed bacterial growth in most of the agar media tested. Bacterial survival after pasteurisation was observed in only 3 samples and, in these cases, the microorganisms isolated belonged to the species B cereus. Furosine could not be detected in any of the samples, whereas changes in lactose, glucose, and myoinositol concentrations after holder pasteurisation were not relevant. Lactulose was below the detection limit of the analytical method in nonpasteurised samples, whereas it was found at low levels in 62% of the samples after holder pasteurisation. The lactation period influenced myoinositol content because its concentration was significantly higher in transition milk than in mature or late lactation milk samples.
Conclusions: Holder pasteurisation led to the destruction of bacteria present initially in donor milk samples, except for some B cereus that did not display a high virulence potential and did not modify significantly the concentration of the compounds analyzed in the present study.
*Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Universidad Complutense de Madrid
†Servicio de Neonatología, Hospital Universitario 12 de Octubre
‡Departamento de Bioactividad y Análisis de Alimentos, Instituto de Investigación en Ciencias de la Alimentación, Madrid, Spain.
Address correspondence and reprint requests to Dr Juan M. Rodríguez, Departamento de Nutrición, Bromatología y Tecnología de los Alimentos. Facultad de Veterinaria, Universidad Complutense de Madrid, Avenida Puerta de Hierro, s/n, 28040 Madrid, Spain (e-mail: firstname.lastname@example.org).
Received 12 April, 2011
Accepted 8 July, 2011
The present study was supported by the 110AC0386 (CYTED), CSD2007-00063 (FUN-C-FOOD, Consolider-Ingenio 2010), and AGL2010-15420 projects from the Ministerio de Ciencia e Innovación (Spain), and by projects FIS PS09/00040 (Ministerio de Sanidad y Consumo, Spain) and S2009/AGR-1469 (Comunidad de Madrid, Spain).
The authors report no conflicts of interest.