Abstract: According to W D Bigelow’s sterilization theory, a programmable DAQ system based on PC (Personal Computer) open loop was built to provide continuous measurement of cold spot temperature and accumulate its F value during can sterilization process. The hardware of the system consisted of a temperature sensor, a DAQ instrument, a PC and some other fittings. The probe of the sensor was fixed on the cold spot and thus, the DAQ instrument brought the temperature message to the PC for further processing via RS-232 serial communication. The designed fittings involved a sensor connector nut, a sensor protection tube, a lock nut and packing glands, which could help to introduce the probe into the product, make the probe more stable and maintain the seal during sterilized processing. The specific application program was developed in LabVIEW environment. It could function as data receiving, F Value calculation, real time curve drawing, data saving and outputting. Experiments showed that the whole system can be applied to determine and monitor the temperature changes on-line in canned food sterilization; the system also can offer an off-line reference data for formulating process parameters.

Key words: can sterilization, cold spot, F value, virtual instrument, data acquisition(DAQ), serial communication