Which of the following is true about holders method of pasteurization

Pasteurization: Pasteurization is a technique in which heat is applied to liquids to kill potential agents of infection and spoilage, while at the same time retaining the liquid's flavor and food value. Pasteurization is an example of sterilization at a temperature <100degC. Methods: 63degC for 30 min (Holder method) and 72degC for 15-20 sec (Flash method) followed by rapid cooling to 13oC (Better method) Pasteurization kills nearly 90% of bacteria in milk except ceain bacteria like Coxiella burnetti which is resistant to Holder's method of sterilization but killed by Flash method of Sterilization.