Thanks to Mr. Wee who has presented and deliberated in detail the superiority and implementation of Constant Back Pressure System (CBPS) & Pros & Cons of FFB splitter for sterilisation in our Ask the Experts. From the response of members, it looked like most members has successfully implemented the CBPS in their own mills without much of a problems. Well done.
Now as we know, whatever the sterilisation method, the ultimate goal is to reach a sterilisation temp of about 130 deg C and hold for 30-40 mins to achieve a good sterilisation.
As a mill process engineer, how could I perform my daily routine check to ensure my sterilisation is satisfactory? Some mills’ steriliser temperature gauge are not working most of the time.
Any SOP for the supervisor or Process Engineer?
Sterilisation Temperature Discussion of Sterilisation is never complete without mention of sterilisation temperature. Sterilisation of FFB is cooking of fruit at 131 deg C for 30~40 mins with wet steam. There are 2 parameters of concerned i.e. the temperature and time. The saturation temperature of steam at 40psig should be 141 deg C. However, this temperature would be lower if deaeration is unsatisfactory. In conventional sterilisation, deaeration is achieved by displacement of air with steam distributed from the top distribution chamber slowly pushing the air out of cages loaded with FFB through the bottom drain manifolds along the steriliser. The effectiveness of this displacement may be compromised by: 1. Broken top chamber rendering uneven distribution of steam. 2. No or insufficient breathing holes on Cages side plates 3. Choked drain manifolds short circuiting flow of air/steam. And introduction of FFB splitter inadvertently mislead us to shorten sterilisation time as most of us tend to use USB as a guide for satisfactory sterilisation. A 30 mins cooking time at a minimum of 131 deg C is recommended. The CBPS of sterilisation provides an optimum system in achieving the sterilisation temperature but subject to factors mentioned above. It is the routine responsibility of Mill Engineers to check and ensure the required sterilisation temperature of above 131 deg C is attained over the 30mins under constant 40 psig pressure for each and every cycle. In traditional practice, the steriliser recorder was a Pressure & Temperature Recorder which is seldom used nowadays for whatever the reasons. Therefore, the minimum practice shall be a temperature gauge installed in front of the steriliser door for easy reading to check and confirm the required temperature is reached for every cycle. If temperature of 131 degree C is not reached, actions must be taken.