Bacteriological quality of homologous breast milk.

Bacteriological quality of homologous breast milk Sir, In a recent report Carroll et al.1 showed that the bacterial colony counts of early drip breast milk did not differ from midstream samples and they concluded that early milk was suitable for milk banks and should not be discarded. We report our findings of 'significant' bacterial counts in early milk samples, since we were interested in the bacteriological quality of breast milk ingested by the mother's own baby. In a study to investigate the bacterial content of homologous breast milk the first 2-3 ml milk were collected by manual expression into sterile containers before the infant suckled. Quantitative bacterial counts were performed as described.2 Ninety samples ofexpressed breast milk (EBM) were tested from 45 mothers (Figure). The volume of 21 samples was insufficient for satisfactory quantitative counts and only the presence of pathogens could be determined. Thirty-six (66%) of 69 samples had counts >2500 organisms/ml and altogether 'potential pathogens' were isolated from 14 (15 %) of 90 samples of the first 2-3 ml of EBM. Our earlier results2 indicated that 33% of EBM aliquots had counts >2500 organisms/ml from both hospital and domiciliary donations. It is clear from the figures of Carroll et al.' that 4 (20%) of 20 paired milk samples had 'potential pathogens' by our criteria,2 while 9 (47 %) of 19 had initial counts at or > 107 colony counts/litre. From these bacteriological results it is evident that both groups of mothers in the two reports were providing milk for their own babies which on our previous criteria2 we would not give to unrelated babies. The offspring of our mothers did not show clinical evidence of neonatal infection although clearly they D All samples 30. Samples with Figure Resilts of 90 samples of expressed breast milk from 45 mothers. ingested some 'potential pathogens' and large numbers of non-pathogenic organisms. We could not determine whether the origin of the organisms was maternal or non-maternal, but if there were some non-maternal organisms it is unlikely that specific homologous anti-bodies were present in the ingested milk or colostrum. The mother's own organisms are probably less harmful to her own child because of the antibodies in her milk which reflect her own immunological experience.3 Other non-specific protective mechanisms, such as gastric acidity, may also be important in reducing the infective risk of 'potential pathogens'. Much controversy exists about the relative virtues of pasteurisation …