High temperature cooking and sterilization is an effective method to prolong the shelf life of food, and it has been widely used by many food factories for a long time. Commonly used retort pouches have the following structures: PET//AL//PA//RCPP, PET//PA//RCPP, PET//RCPP, PA//RCPP, etc. The PA//RCPP structure is widely used. In the past two years, food factories using PA/RCPP have complained more about flexible packaging material manufacturers, and the main problems reflected are delamination and broken bags. Through investigation, it is found that some food factories have some irregularities in the cooking process. Generally speaking, the sterilization time should be 30 ~ 40min at a temperature of 121C, but many food processing companies are very casual about the sterilization time, and some even reach the sterilization time of 90min.
For the experimental cooking pots purchased by some flexible packaging companies, when the temperature gauge shows 121C, the pressure indication value of some cooking pots is 0.12 ~ 0.14MPa, and some cooking pots are 0.16 ~ 0.18MPa. According to a food factory, when the pressure of its cooking pot is displayed as 0.2MPa, the indication value of the thermometer is only 108C.
In order to reduce the quality impact of differences in temperature, time and pressure on the quality of high-temperature cooking products, the temperature, pressure and time relays of the equipment must be calibrated regularly. We know that the country has an annual inspection system for various types of instruments, among which pressure instruments are mandatory annual inspection instruments, and the calibration cycle is once every six months. That is to say, under normal circumstances, the pressure gauge should be relatively accurate. The temperature measuring instrument does not belong to the category of mandatory annual inspection, so the accuracy of the temperature measuring instrument should be discounted.
The calibration of the time relay also needs to be calibrated internally on a regular basis. Use a stopwatch or time comparison to calibrate. The calibration method is suggested as follows. Correction method: Inject a certain amount of water into the pot, heat the water to boiling to the extent that it can submerge the temperature sensor, and check whether the temperature indication is 100C at this time (in high altitude areas, the temperature at this time may be 98 ~ 100C) ?Replace the standard thermometer for comparison. Release part of the water to expose the temperature sensor to the water surface; cover the pot tightly, raise the temperature to 121C, and observe whether the pressure gauge of the cooking pot at this time indicates 0.107Mpa (in high altitude areas, the pressure value at this time may be (0. 110 ~ 0. 120MPa). If the above data can be consistent during the calibration process, it means that the pressure gauge and temperature gauge of the cooking pot are in good condition. Otherwise, you should ask a professional to check the pressure watch or thermometer for adjustment.
Post time: Jun-24-2022