PIMM™ Projected Product Temperature (PPT)
THE MKT CALCULATION
The underlying algorithm / calculation we utilised to produce our PIMM™ Projected Product Temperature (PPT) is Mean Kinetic Temperature (MKT).
WHAT IS MKT?
MKT is an expression of cumulative thermal stress experienced by a product at varying temperatures during storage and distribution. MKT is not a simple weighted average. The calculation of MKT gives the higher temperatures a greater weight when computing the average than would a simple numerical average or an arithmetic mean.
WHO USES MKT?
The Pharmaceutical industry has widely used the calculation for decades and is deemed compliant by the FDA as an indicator to verify if a particular perishable has exceeded storage conditions. HEAT ACTIVATION VARIABLE (∆H) MKT utilises the default activation energy of 83.14472 kJ/mol for its calculation. This can be modified for a specific products profile, but any value between 60 and 100 kJ/mol (which covers most foods/liquids) will have only a small effect on the final value.
WHEN DOES MKT FAIL?
Extreme and sudden heat (ex: cooking product) will damage the product before the MKT simulated calculation would show a violation. The problem is not highlighted in food distribution where food is considered “tightly controlled” during the supply chain.
REAL-TIME MONITORING OF PRODUCT TEMPERATURE
The key benefit of our PIMM™ PPT simulated temperature is that it is regenerated with each new air temperature reading we receive from the telematics hardware device. Our default setup is to receive and recalculate PPT every five minutes. This allows our system to be predictive and warn our distributor customers of a potential temperature incident before it becomes a food quality or safety risk.
KEY FEATURES OF PIMM™ PPT
While the underlying calculation behind our PIMM™ PPT is based on the mean kinetic temperature calculation, through field testing and thousands of simulations against route data in our database, Procuro has enhanced the algorithm to give even more accurate simulated temperatures through customised settings and variable inputs. Here are some of the variables and customisations we can deploy to give our customers more accurate product simulated temperatures:
1. ADJUSTABLE STARTING TEMPERATURE & STORAGE DURATION
Starting Temperature: Starting Temperature can be set to a default temperature (ex: 2 C for lettuce), or we can use a probed temperature of a designated product during loading. This allows for custom starting temperatures per route to reflect more accurate product simulated temperatures. Storage Duration: The calculation assumes that the product was stored at the starting temperature for X amount of hours (ex: 12-24 hours) prior to the trailer loading. The storage duration gives the calculation some “weight” to offset initial warm spikes that can be seen during loading/staging, where product temperature is normally not impacted.
2. CUSTOMISED “PRIMARY” AIR TEMPERATURE SENSORS
All product simulated temperatures are based off of an air temperature reading from the trailer. Procuro supports a customised “primary” sensor for each specific asset (trailer / truck). The two most common primary sensors are: 1) Reefer return air (for trailers that have integration to reefer data) 2) External air sensor Note: The reefer supplied data (ex: reefer return air) is often not available when reefers are shut off, which causes large data gaps during deliveries (when product is exposed to the worst thermal conditions).
3. ROLLING MONITORING WINDOWS
For longer transits, the starting storage duration can introduce too much influence on the product PPT calculation. We have the ability to modify our algorithm to only include temperature readings from the last X hours (ex: 4 hours) of the current transit to provide a more accurate current temperature of the product. This is especially helpful for products that are more susceptible to thermal abuse in a shortened period/duration (ex: lettuce).
PRODUCT SPECIFIC RULES
While Procuro recommends running a generic product profile for frozen and chilled goods, since a distribution route consists of multiple products (SKUs) with different temperature profiles, we can support running PPT analysis on specific product profiles. To achieve that we would look to modify the following: 1) Heat Activation Variable (∆H): food supplier/producer would provide the exact value to utilise (can range between 60-100 kJ per mol) 2) Starting Temperature & Storage Duration: investigate what the product normally starts at when loading and for how long it is held. 3) Rolling monitor window hours: during validation test we will analyse the proper monitor window hours to apply for specific products.
OUR VALIDATION PROCESS
Procuro would run a 1-2 week product temperature study where we would monitor three temperature components side-by-side during live routes at one specified DC site.
1. Primary air temperature (reefer return air / ambient wall sensor)
2. Data-logger or probed logger placed inside product (to monitor actual product temperature)
3. PIMM™ PPT The PIMM™ PPT will be simulated and calculated by the Primary Air Sensor. Procuro will run the PPT calculation through thousands of simulations adjusting the variable fields in our calculation. The goal is to demonstrate a successful PPT “mimic temperature” compared to the product temperature collected on the data-logger (within 0.5 degrees Celsius). Variables:
1) Heat Activation Variable (∆H)
2) Starting Temperature
3) Storage Duration
4) Rolling monitor window hours All results will be shared with our customer to make final decision on the variables to implement for their customised calculation.
Learn more about our Projected Product Temperatures (PPT):