This is a vendor to vendor issue not just a transportation issue
Slight deviations in transit temperature based on, among other things, the location and accuracy of the temperature recorder, are normal. What constitutes a “slight deviation” will vary, but Blue Book’s Transportation Guidelines provide the following rule of thumb–
(6.2) Refrigeration (or “reefer”) systems should be set to run continuously, and not on a start-stop or cycle basis. Slight deviations in transit temperature based on, among other things, the location and accuracy of the temperature recorder, are inevitable and permissible. What constitutes a “slight deviation” will vary, but as a rule of thumb temperatures within the trailer should not deviate more than four (4) or five (5) degrees Fahrenheit from the agreed-upon transit temperature. If a temperature range is specified, any deviation will be assessed from the midpoint of the specified range. A temperature variance lasting less than twelve (12) hours may also be categorized as a slight deviation, depending on the extent of the variance, the relative perishability of the commodity, and other circumstances. E.g., a shipment involving multiple pick-ups or drops may be expected to experience temperature variance during loading and unloading. Nothing in this Section should be interpreted to suggest a temperature deviation was slight, and therefore permissible or excused, when product has been frozen in transit.
This provision is intended to be used as a benchmark to help buyers, sellers, and carriers assess whether a given temperature report suggests that the carrier properly maintained air temperatures in the trailer or not.
When applying this rule of thumb, the first thing to keep in mind is that it is just that—a rule of thumb. It is intended as a first step in the temperature assessment. Applying this rule of thumb too rigidly misses the point.
Let’s consider, for example, a scenario where the readings from a portable temperature recorder indicate air temperatures in the trailer were 12-15 degrees too warm for 10 hours, and the commodity was raspberries.
Clearly the temperatures are way out of range, but the duration of the variance is just 10 hours. Does this mean Blue Book would classify these temperatures as a slight deviation? No. In fact, we would consider readings at this level, for this amount of time, to be strong evidence that the carrier failed to properly maintain transit temperatures.
So, what good is a rule of thumb you might ask?
Well, we would suggest it helps assure consistency between temperature assessments (many of you assess dozens of temperature reports a year) by providing a standard benchmark to compare with the temperature readings in question. Also, comparing a standard to a specific shipment naturally draws attention to any factors or circumstances that may have been exceptional about the shipment under review.
Using this approach to assess our raspberry scenario would go something like this:
First step: Do the temperature readings in question, strictly speaking, fall within the permissible variance set forth by the rule of thumb? Yes. Although the temperature readings were warm, they were only out of range for 10 hours.
Second Step: Are there any exceptional factors or circumstances involved that would suggest temperatures were not properly maintained? Yes. Not only are raspberries one of the most highly perishable commodities (therefore requiring the utmost of care) but the temperature readings presented here were exceptionally far out of range for an extended period of time.
Properly applied, this is an approach that can help facilitate constructive dialog when disputes arise. Produce buyers, sellers, and carriers tend to view temperature readings from different vantage points, but ultimately all parties have a shared interest in reviewing, and hopefully resolving disputes, in a consistent manner.
Of course, even when using a common standard, close calls and differences of opinion will arise. In these cases, compromise solutions between reasonable people can help establish the trust upon which long-term business relationships are built.