Refrigeration Index Calculator
The Refrigeration Index (RI) is an index for the log growth of E. coli. It predicts the expected growth of E. coli on meat from temperature and other data. The model has values for pH, water activity and lactate concentration which in addition to temperature, all affect the growth rate of E. coli. The current RI model allows for the user to enter data on temperatures of the product over time. The other parameters are set by choosing the type of product.
RI has replaced the previously termed Hot Boning Index (HBI) and will now be used more broadly than the HBI to assess effectiveness and regulate meat refrigeration processes throughout the Australian industry.
The central idea of the RI is to measure the performance of the chilling process until all the sites of microbiological interest are at or below 7'C. This is the temperature at which E. coli and Salmonella stop growing.
The image below shows individually wrapped (left) and vacuum (right) packed rumps of where the placement of thermocouples and contact areas should be when taking measurements.
Individually wrapped (left) and Vacuum (right) packed rumps showing placement of thermocouples and contact areas
It is important to note that the RI, as an indication of the effectiveness of refrigeration, is NOT a prediction of the number of E. coli in the product.
MLA have developed an updated version of the RI Calculator. This fully responsive tool runs on current versions of Chrome, Firefox, Safari and also in Internet Explorer 11 on the Windows Platform. The tool also runs on both IOS* and Android devices.
*Note: On IOS devices the tool is unable to browse the local file system to load files, though users are still able to paste data into the interface to create and view results.