On the inactivation of Brucella abortus in naturally contaminated milk by commercial pasteurisation procedures.

Following concern about the recent publication indicating the possible ability of Brucella abortus to survive commercial pasteurisation of naturally contaminated milk, such milk was subjected to biological (BT), serological and bacteriological tests. The raw milk was Brucella Milk Ring Test positive and biotype I was isolated from 4/5 BT guinea pigs, the one tested being seropositive to the Rose Bengal Test, and with serum agglutination and complement fixation titres of 160 and 36 international units respectively. After batch (63 degrees C/30 min) and high temperature, short time (72 degrees C/15 sec) pasteurisation, all 10 BT guinea pigs were bacteriologically and serologically negative, indicating that officially approved methods of commercial pasteurisation rendered naturally Brucella-contaminated raw milk safe for consumption.