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Produce Pointers

Warm pulp temperatures; cool temperature tapes

The Problem: High pulp temperatures at destination.

The Key Point: Packaged product may trap heat from respiration regardless of air temperatures within the conveyance.

The Solution: All available temperature information must be carefully considered before conclusions are reached.

QUESTION:  We are a produce distributor with offices on both coasts.  We recently purchased a shipment of baby carrots by rail (and dray trucks) from California for delivery to a retailer in New England. Upon arrival the carrots were rejected because three of the four packs of carrots were pulping at 47 to 49 degrees.  Surprisingly, however, both portable temperature recorders — which were loaded with the product on the first dray truck and remained with the product until delivery in New England—showed good steady temperatures at approximately 35 degrees.  Additionally, the reefer download from the railcar looked good, and one of the packs of carrots pulped fine at destination.  Both the carrier and the shipper are denying responsibility but obviously something went wrong somewhere.  A third-party perspective may help.

ANSWER:  We think it’s important to recognize this was packaged product and that the pallets appear to have been shrink-wrapped.  Therefore, these carrots would have been shielded from direct exposure to the air within the railcar (and trailers) by both the packaging and the shrink wrapping of the pallets; and, significantly, the packaging would have retained heat from respiration coming from the carrots.  It is not uncommon or abnormal for packaged product to pulp at temperatures a few degrees warmer than the air temperatures within the trailer as heat from respiration is captured.

In light of the multiple temperature records showing normal temperatures, we believe the most likely explanation for the warm pulp temperatures recorded at destination is that three of the four packs of carrots were inadvertently loaded warm by the shipper, and that these warm temperatures accelerated respiration of the product causing heat within the packages to build.  This explanation is, in our view, consistent with the fact that not all of the product pulped warm at destination, and the good air temperatures recorded by multiple temperature recorders.

Because no pulp temperatures were noted on the bill of lading by the shipper or the driver, we cannot know the pulp temperatures at shipping point with any certainty.  However, in reviewing the documentation you have provided, we see the rail carrier recorded pulp temperatures prior to the rail portion of this trip indicating pulp temperatures of 38.3, 38.9, and 39.1 degrees.  And while these temperatures are significantly cooler than the destination pulp temperatures, it must be remembered that elevated temperatures increase the rate of respiration dramatically (in a “logarithmic” rather than linear fashion), and so we believe it is possible the temperatures in the high-thirties on the first day of the trip could have elevated to the high-forties over the course of the next 7 to 8 days, as the packaging trapped heat from the carrots.

Although the pulp temperatures recorded by the carrier prior to the rail portion of the trip were not verified (i.e., the pulp temperatures were not taken in the presence of the shipper or a disinterested third party), the warm pulp temperatures recorded by the carrier do fit with the other pieces of the puzzle here: namely, the good air temperature reports from multiple temperature recorders (portable and reefer-based) and the arrival of some of the carrots without temperature problems at destination.  Taken together, we believe the documentation presented suggests the carrier properly maintained air temperatures in transit and that your shipper may be responsible for the losses incurred.


Your questions? Yes, send them in.  Legal answers? No, industry knowledgeable answers. If you have questions or would like further information, email


Doug Nelson is vice president of the Special Services department at Blue Book Services. Nelson previously worked as an investigator for the U.S. Department of Agriculture and as an attorney specializing in commercial litigation.