to add to EagleEyes comments,
Phillic/Phile - means "loving" so thermophiles "love" or grow well at high temperatures. The actual temperatures that need to be considered could depend on your customer requirements and what your products are used for and what temperatures are of concern with your manufacturing process. In the dairy industry we're concerned about organism that can grow around the 50-60°C range.
Thermoduric - they endure high temperatures - they don't love it but can survive short times of exposure to high temperatures.
Mesophilic (Meso - middle/modeate) these microbes are what are typically counted/tested for under the "standard plate count"(SPC) aka - "total plate count" (TPC) test methodology - which is typically incubated at 30°for 72 hours.
Thermophiles are processed using the same test methodology as for SPC but the difference is that they are incubated at 55°C for 48 hours.
Thermodurics are tested by exposing the sample to a high temperature eg 63°C for 30 mins (pasteurization) rapidly cooled and then, plated out and treated like a SPC test - i.e. 30°C for 72 hours.Go to the full post