Our CheckPoint® I B23H is a 4 day label at 0°F, and signals partial thaw events almost immediately, as detailed below.

The B23H CheckPoint® I label is ideal for monitoring very sensitive storage of frozen food items, especially ice cream, or those with no tolerance to partial sub-freezing thaw.  The characteristics of this label are easy to understand:

• If a product is kept exactly a 0°F (-18°C) for the whole "temperature history" of the product, then the B23H label will show a color change on Day 4 after activation of the label.

• Any temperature abuse to the frozen commodity will shorten the time to the color change , reflecting a shortened shelf life of the product, or warning of a dangerous thaw

Some example characteristics of the B23H are shown in the following example:

In each case, the "standard" time run of the label (4 days at 0°F) is shown.  The shortening of the color display with different temperature abuse situations is shown.  The red lines indicate the temperature profile in an example abuse situation.  

A 
In this example, the product is kept at the required 0°F for one day, then the temperature rises to 36°F.  This is a serious thaw event.  The color change occurs almost immediately, signaling that the product has experienced unacceptable temperature abuse.  The color remains yellow, even if the product is subsequently re-frozen.

B
This example simulates a brief and non-severe departure from ideal cold storage conditions.  At day 1, there is a 5 hour rise to 15°F.  There is no immediate color change in the B23H label, but the total time to the color change is appropriately shortened about 18 hours from the "standard" time of 4 days.  This shortening appropriately reflects the effect of the mild temperature abuse situation on the frozen commodity. The color remains yellow, even if the product is subsequently re-frozen.

C
Example C shows a protracted temperature abuse situation.  The temperature rise is still sub-freezing, but is long enough to compromise product wholesomeness.  The B23H label changes color just over a half a day from the inception of the temperature abuse, signaling that the shelf life has been too compromised by the high temperature situation.  The color remains yellow, even if the product is subsequently re-frozen.

D
Example D shows a protracted temperature abuse situation, but at a much lower temperature.  The temperature rise is sub-freezing and only a few degrees above the ideal 0°F, but is long enough to compromise product wholesomeness.  The B23H label changes color just before day 3, signaling that the shelf life has been too compromised by the high temperature situation.  This is substantially shorter than the time for color change if the product was maintained at the ideal 0°F.  The color remains yellow, even if the product is subsequently re-frozen.

The B23H label is an ideal monitor to protect frozen food commodities kept for very short periods in deep frozen storage, or those with no tolerance of partial subfreezing thaw.  It acts as a safeguard against later problems with product consistency, quality and wholesomeness.