Written by Genevieve Shattow
November 8, 2017
Written by Genevieve Shattow
If your stores are still using paper logs to monitor temperature, you may not have a full understanding of how your equipment affects your products. With traditional twice-daily temperature logging, there’s no way to know what’s happening inside of coolers and freezers throughout the day. Temperatures can fluctuate dramatically in between measurements, even if everything reads to your cooling standard at the time of logging. This is why more pharmacies and food retailers are making the transition to continuous monitoring systems.
Let’s take a look at three cases showing why continuous monitoring is the right solution for your stores. Each figure below shows two days of temperature readings. The vertical orange lines are 8 a.m. and 8p.m. each day — representing the CDC-recommended twice per day temperature monitoring. The red and blue dashed lines are the CDC-recommended upper- and lower-temperature thresholds for refrigerated pharmaceuticals.
Power can be cut off to coolers or freezers for any number of reasons, ranging from neighborhood-wide outages in the aftermath of hurricanes to energy-saving settings in buildings where power turns off in certain outlets overnight.
This figure shows a regular overnight power loss, where the cooler loses power from 9:30 p.m. to 6 a.m.. Stores are rarely staffed during this time, and by 8 a.m., the temperature is back in range. A temporary loss of power (and the resulting 10-hour excursion) will likely go unnoted. In this particular example, an employee might even turn the cooler’s temperature up, as the compressor cycle sits right on the lower threshold of CDC-recommended temperatures.
The graph above shows a standard compressor cycle, and the graph below shows what happens to that cycle at the time of restocking.
This figure is an example of what can happen to a cooler's temperature when there’s a large influx of product. If the product is warmer than the air in the cooler, it raises the temperature of the whole environment. The compressor eventually brings the temperature back in range, but we see here that the peak of the compressor cycle doesn’t fall below the upper threshold between restocking at 9 a.m. and 5 p.m. This is less of a problem in pharmacies where the cold chain is maintained and the product is the same temperature as the cooler. For the front of store coolers, or if a cooler is mixed-use, re-stocking can lead to a surprisingly lengthy excursion.
Many coolers and freezers have built-in defrost cycles to prevent the buildup of ice. These peaks in temperature are usually very regular and on 4-12 hour cycles. They can wreak havoc on manual temperature monitoring — especially if the readings are taken at the same two times every day. One possible outcome is that the measurements will always be taken during a regular compressor cycle and the defrost periods will be missed entirely, as shown above. Alternately, measurements always taken during a defrost cycle will cause the store employee to think the average temperature is much warmer than it actually is, leading them to turn down the cooler to freezing temperatures.
Twice-per-day readings have historically been best practice, but conclusions drawn from them are susceptible to gaps in the data. Whether it’s a door left open, a power outage or a defrost cycle, temperature fluctuations are often missed. To deal with this, many retailers are now making the switch to digital temperature monitoring.
Continuous monitoring systems allow you to see dangerous excursions that might otherwise be missed, such as power outages. Over-compensating for minor excursions, such as during a defrost cycle, can also be avoided, giving your business more reliable control over cooling. A thorough understanding of what’s happening inside your equipment helps you better protect your customers and your brand.
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