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THERM – FAQs

  1. How do I enter time and temperature data from a datalogger?

    Entering time and temperature data from a datalogger can save you a lot of time. See the Instructions page for step-by-step instructions.
  2. What does "% of LP" mean in the graphical results?

    LP means lag phase, which is the time that must elapse before the pathogen cells are capable of growing (multiplying). The % of LP indicates how much of the lag phase has elapsed.
  3. What does "logs of growth" mean in the graphical results?

    "Log" is short for logarithm. Logarithms are a shorthand way of describing numbers. Each "log" of growth indicates a 10 X increase in cell numbers. So, 0.4 logs of growth is less than a 10 X increase, 1.0 logs is a 10 x increase, and 2.0 logs is a 100 X increase.
  4. What does "Temp Used" mean in the tabular results?

    THERM is programmed to assume a "worst case" situation for temperature control. For any time interval (the time elapsing between the previous time entered and the current time entered), THERM will use, as the base for calculations, the warmer of the two temperatures entered.
  5. What is "LPD" in the tabular results?

    LPD is the lag-phase duration at the "temp used". This is the amount of time that must elapse before the pathogen begins to multiply (grow).
  6. What is "%LPD in interval" in the tabular results?

    This is the % of the LPD that elapsed in the interval.
  7. What is "Cum % LP" in the tabular results?

    This shows the cumulative total of the % of lag phase in all the intervals up to the present.
  8. What is "Growth in interval" in the tabular results?

    This shows how many "logs" of growth occurred during the interval.
  9. What is "Cum growth" in the tabular results?

    This shows the total cumulative amount of growth in all of the intervals so far.
  10. What if a row in the tabular results show no entries for "Rate", "LPD", "% LP in interval", "Cum % LP", "Growth in interval", or "Cum growth"?

    This output for a given time interval means that the temperature used for that interval was too cold to support growth of the pathogen.
  11. Why do my results always show that E. coli O157:H7 does not grow on poultry?

    In our research, we did not test for the growth of E. coli O157:H7 in poultry because chickens, turkeys, etc. do not normally carry this organism. Therefore, THERM results will not show growth of E. coli O157:H7 on poultry products.
  12. Why does the screen sometimes go faint?

    Why do I sometimes have to wait before THERM will allow me to type in a value? When these things happen it simply means that THERM is performing a calculation based on a previous command. Be patient and wait for the screen to appear normal; then continue entering data.
  13. Who do I call if I have questions about my results?

    Wisconsin Meat Processors should contact Dr. Steve Ingham, Extension Food Safety Specialist, at 608-265-4801 or scingham@wisc.edu. Meat processors in other states should contact their local HACCP coordinator.
If you have questions or comments about the Cooperative Extension Web site or you have trouble accessing this page, require this information in an alternative format or wish to request a reasonable accommodation because of a disability contact: bhingham@wisc.edu. We follow the Terms of Use and Privacy Policy of the University of Wisconsin-Extension. This document last modified March 16, 2010 .