Ochratoxin A in cow's milk and in human milk with corresponding human blood samples

Abstract

A method for determining ochratoxin A in milk has been elaborated in which the sample was subjected to a liquid-liquid extraction step and then purified on a silica gel column packed in a Pasteur pipet. The purified samples were analyzed by ion-pair liquid chromatography with fluorescence detection. The detection and quantitation limits for determination of ochratoxin A in cow's milk were 10 and 40 ng ochratoxin A/L milk, respectively. The same limits were valid for the analysis of human milk. A total of 36 cow's milk and 40 human milk samples were analyzed. All samples were collected in Sweden. Ochratoxin A was found in 5 (14%) of the cow's milk samples (range 10-40 ng/mL) and in 23 (58%) of the human milk samples (range 10-40 ng/L). Blood samples were collected from the mothers who gave milk samples. A total of 39 samples were analyzed. All blood samples contained ochratoxin A in concentrations exceeding the quantitation limit (60 ng/L blood). The mean concentration of ochratoxin A in the samples was 167 ng/L blood (range 90-940 ng/L). The concentration of ochratoxin A in human milk was < or = 0.1 of that in the human blood.