When hauling the more perishable produce items such as strawberries, knowing your reefer unit, maintaining proper temperature and taking a pulp temperature at shipping point becomes even more critical. Doing things right results in delivering a better product to your customers, as well as reducing claims and load rejections.
These points are among some important findings in a study released last year, Comparison of Pallet Cover Systems to Maintain Strawberry Fruit Quality During Transport. As the title indicates, the study compares modified air controlled strawberry shipments using carbon dioxide (CO2).
Following up on that report, HaulProduce.com had an extensive interview with Rich Macleod of TransFresh Corp. of Salinas, whose product Tectrol came out looking pretty darn good when compared with competing companies offering controlled atmosphere bags covering palletized loads of strawberries.
The project was a combined effort of the University of California, Davis and the University of Florida in conjunction with the USDA.
“What this (study) demonstrates is when you put a bag over the pallet, you are going to get some in-transit warming,” Macleod observes. “It doesn’t matter whether it is a Tectrol (application) or somebody else’s bag because the warming is about the same for all of them.”
Where Tectrol shined in the study was the quality of the berries upon arrival after the cross country hauls from California to the east coast.
But back to the issue of in-transit warming. Rich points out when a palletized load is entirely bagged, the driver has to account for warming when adjusting the refrigeration unit set points accordingly at a colder temperature than if the load were “naked.”
He says, “I believe you can run a fully bagged Tectrol load (of strawberries) at 30 degrees F. if your (reefer) unit is well calibrated and your unit was built within the past four years.”
However, realistically Macleod knows most drivers prefer a 36-degree F. setting. As they become more familar with these type of loads they find out one can drop the setting to 34 or even 32 degrees.
“They (drivers) should not have issues with warmer product, if it is bagged. And they should not have any issues with frozen product. There are a number of drivers that have been incredibly successful handling Tectrol loads at 32 degrees F., but they know their units inside out and have them calibrated. They know what the floors are and the coldest temperatures that unit will be. Thirty-two degrees is a reasonable compromise.”
Macleod stressed that even if the fruit has been properly pre-cooled, carriers have to realize those bagged pallets will increase the temperature.
In fact the study itself points out in shipments with non covered pallets, the clamshell packaged strawberries remained at 32 to 35 degrees F. However, pallets covered with bags resulted in the temperature increase of three to four degrees by the time it arrived at destination.
“The rise in temperature during shipments indicate the trailers were unable to maintain the recommended 32 degrees F….” the study states.
What can a driver do if the pallets are already covered with CO2 filled bags upon arrival at the dock?
Although it is too late for a visual inspection of what is being loaded by the driver, Macleod says, “a well run (shipping) company should allow the driver to take a pulp temperature and they (shipper) should provide tape to reseal that hole (made by the driver to take the pulp temperature). It is a common practice and shippers respect that.”
(This is Part 2 0f 5, featuring an interview with Rich Macleod, vice president, pallet division North America for TransFresh Corp., Salinas, CA. He has been with company since 1976, and has a masters degree in post harvest science from the University of California, Davis.)