Opinions vary over where the greatest vulnerabilities lie, but a nuanced mix of harnessing new technologies, fine-tuning practices, conducting clear communications and fostering interpersonal skills will go a long way to securing higher quality food with better shelf life.
If the terms FEFO, cut-to-cool or even RFID are foreign to you, there may be room for improvement in your fresh produce cold chain. But all that still accounts for little if your trucker relationships are frosty.
Despite tremendous progress seen over the past decade, the game of keeping fresh fruits and vegetables optimally cool for longer can still be lifted.
Ken Lund, vice president of operations at Allen Lund Company in La Cañada Flintridge, CA, says the fact loads are mostly transported on pallets has led to better cold chain maintenance as a result of improved air circulation that can flow underneath the cargo.
“For the most part, the produce industry does a great job of getting product to marketplace,” says Lund, whose transport brokerage company schedules 1.3 million appointments through its system each year. “We only hear when things go bad, but you don’t hear of the thousands of loads every day that arrive in good order.”
Meanwhile, the proliferation of temperature-monitoring technologies with remote tracking capabilities is holding the chain and its links to account.
“It’s gotten dramatically better with the advent of devices that can go inside the load,” says Lund. “They only cost $20 or $25 more than a passive temperature tracking device to have location and temperature live.”
“We ran a test with a company that did 500 loads a month of produce and we put on live active tracking of both location and temperature – their claims dropped by over 75 percent.”
These systems are given a great deal of attention by industry leaders, but Lund believes they are still only being used in between 20 to 25 percent of fresh produce loads.
“We’re seeing it adopted more and more, but we wish it was faster because it just saves everybody time and trouble.”
Emerson Cargo Solutions is one of several companies that have been active in these innovations. In 2019 the St Louis, MO-based group introduced its GO Real-Time Tracker as a flexible monitoring solution for perishables.
“Our latest product introduction provides the versatility to help customers simultaneously monitor ambient temperature, measure relative humidity and take pulp temperature readings for produce and other perishable products,” says Amy Childress, Emerson Cargo Solutions’ vice president of marketing & planning.
She claims the technology is ideal for when shippers want to monitor the internal temperature of products with a probe, which can be particularly helpful for sensitive commodities like berries, melons and other fresh-cut produce items.
She notes a big shift in the desire for increased technology transparency from supplier to consumer. As part of this, Emerson recently joined the IBM Food Trust to enable actionable data for its network of members.
“With today’s technology advancements, all segments of the cold chain are seeking access to cold chain analytics,” says Childress. “Our industry wants the flexibility to use real-time tracking technologies when warranted but also the freedom to implement traditional temperature monitoring programs using loggers.”
1. UNDERSTAND LOAD TEMPERATURE VARIABILITY
Jeff Brecht, a professor in postharvest biology at the University of Florida (UF), thinks not only does temperature monitoring need to be adopted more widely but in greater numbers within loads due to temperature variability.
“The standard practice is to put one of those data loggers, usually near the rear of the load on the side of one of the pallets so that it can be seen and found easily when they open the doors,” he says. “And because it’s outside of the pallet, it’s really only measuring the air temperature; it’s not measuring the product temperature.”
Brecht points to a study done 10 years ago by Cecila Amador, Jean-Pierre Emond and Maria Cecilia do Nascimento Nunes that mapped temperatures in a pineapple shipping trial from Costa Rica.
Using radio frequency identification (RFID) probes, the researchers found pineapples in the lowest layers of pallets were more at risk of low temperatures that could lead to chilling injuries.
In contrast, if the temperature at the core of the pallet was not reduced enough during pre-cooling, it became a critical point of the load with elevated risk of high temperature abuse.
“We saw some of that as well with our strawberry and tomato work,” says Brecht. “You need to have at least a minimum of three data loggers, because that is really what you need to know what is happening to the produce temperature.
“Variability in the load can be quite significant – 5 to 10°F is not uncommon,” he says. “When there’s that heating from respiration, it’s the center of the load that heats up the most.”
Brecht recommends putting pallets towards the center of the trailer with a brace that prevents them from touching its walls, which can retain heat from the outside.
2. KEEP DRIVERS HAPPY
Kenny Lund of Allen Lund Company says while retailers are doing a better job of receiving now than 10 years ago, they could still give warmer welcomes to truck drivers. Technology has its benefits, but industry advancement can also come from something as simple as a smile and a hot beverage.
“If somebody’s driven five days across country with their produce and they get there and can’t even get a cup of coffee or they have to wait in line, or they’re not treated very well, that really hurts us trying to get more drivers to take on produce,” says Lund.
“They all should go to appointment schedules and not first-come, first-served, because that leads to hassles on the dock, and it leads to hurt feelings,” he says. “The number one reason drivers leave the industry is the treatment they receive.”
Corey Rosenbusch, president of the Global Cold Chain Alliance (GCCA) in Arlington, Virginia, mentions another reason why retailers should avoid letting truck drivers wait too long to unload produce — hours of service limitations
“When their time expires with the new electronic logs, they literally cannot move any longer,” says Rosenbusch. “So when you have warehouses, especially receiving facilities like retailers have, that might hold up a trailer or driver for four hours, which is not uncommon. It disrupts the entire supply chain.”
He explains the consequence of these hold-ups can be a perishable product getting delayed for days.
“If you’re talking about shelf life-sensitive product, that can be quite challenging,” he says. “I think a heightened sense of time at retail receiving would significantly impact things.”
3. SET CLEAR EXPECTATIONS
Mark Petersen, vice president of temperature-controlled transportation at C.H. Robinson in Eden Prairie, MN, says once produce is harvested it is in some state of decay, so any delay can have some impact on freshness at the end of the supply chain.
This is why stakeholders across the supply chain need to be on the same page, with Petersen describing the importance of combining education and experience to establish clear lines of accountability and clarity in people’s roles.
“Because of the speed of the transaction, anything that’s misunderstood on the front end will have that much more of an accelerated degeneration as it goes through the process because you don’t have the time to react to it as much,” he says. “My prediction will be that if people talk more on the front and set clear expectations, they will have a much more successful and more cost-effective supply chain to take them into the future.”
Jeff Brecht of UF says the Food Safety Modernization Act (FSMA) might actually speed up this process of improved communication in the cold chain.
“It’s being mandated that the handlers need to be in communication with each other,” he says. “They all have to have standard operating procedures in terms of food safety that they agree on, like control points and what temperatures need to be maintained.”
“I think the fact they all have to put that down on paper and know what each other is expecting is going to pay dividends in terms of temperature management as well,” he says, adding retailers can play a leading role clearly setting expected temperatures they require on arrival for different commodities.
4. REDUCE ‘CUT-TO-COOL’ TIME
In 2016 Brecht and his fellow researchers in Florida published their findings from a Walmart-funded study on reducing post-harvest strawberry waste. A key aim was to see when a ‘first-expired, first-out’ (FEFO) would be better than the standard ‘first-in, first-out’ practice.
“Because the quality actually can vary, we consider the idea that sometimes it might make more sense to not always send the oldest product out first because something may have arrived at the pre-cooling facility later that is actually not in as good condition,” he says.
The scientists were unable to see how the final result of these studies would go at Walmart stores, but the expected effect was simulated with success.
Brecht understands Walmart is developing a library of images to help identify the quality of incoming produce, which may help for applying a FEFO strategy.
“One of the main things we found… it wasn’t new but we documented something a lot of people were already aware of… was that if you don’t have the produce thoroughly cooled before it’s loaded onto a trailer or whatever vehicle it may be, there’s not only the possibility that it’s not going to cool further but it may very well warm up in transit,” he says.
Gary Campisi, president of Rogers, AR-based Global Produce Solutions, was senior director of quality control at the retailer at the time and was involved in the project.
He says RFID-capable monitoring devices are beneficial for detecting any breaks in the cold chain after fresh produce has been loaded, but there is nothing tracking cut-to-cool time from when the product is harvested to its pre-cooling.
“If the strawberries aren’t pre-cooled to 32° and, for example, they were cooled for only two hours versus four hours, in effect I’ve affected the shelf life long-term for the customer,” says Campisi. “I don’t think it’s any fault of anyone; I just think there hasn’t been a lot of emphasis.”
Mark Petersen of C.H. Robinson also notes the practice of putting ice on top of corn can lead to unintended consequences if done incorrectly.
“If you don’t have the proper amount of experience and education, often times what happens is you just set the unit at 32 or 33°F with that top ice, and what that can do in some cases is freeze the top layer rather than have it start melting,” he says. “It acts as an insulation layer rather than a chill factor – because the water never gets the opportunity to start moving to the product, it can actually cause the product to heat up rather than cool down as intended.”
5. KNOW MIXED-LOAD CHALLENGES
Campisi also discusses the challenges of mixed loads, particularly with mangos and papayas that require warmer minimum temperatures to avoid chill damage.
“Every hour below 50° you’re going to start to damage that fruit [mangos], and it doesn’t show on the outside,” he says. “But people put it on a trailer because they don’t have a choice, and they put it with maybe apples because they want to run it at 34°.”
A 2017 report prepared for the National Mango Board (NMB) by Tampa, FL-based The Illuminate Group found the optimal transit temperature for mangos was 55°F, while pallets shipped without covers would not offer enough thermal protection for standard transit times of two to three days.
“However, the [Tyvek W50] cover with base has shown to be the best option in terms of thermal and moisture protection out of the four commercially available pallet covers,” the group concluded. “Additional usage of new technologies combined with existing pallet covers may allow for a better performance, thus protecting the entire pallet from chilling injury for 72 hours.”
Mark Petersen notes honeydews and cantaloupes are another example of a mixed load challenge; they are grown together, but the former is more temperature-sensitive.
“The people who put those tenders together will pick a type of temperature in between that puts each of them at the least amount of risk,” he says, noting pallets can also potentially be wrapped for added protection.
6. TACKLE INTERNATIONAL TRANSPORT HURDLES
Janet Ramos, sales director at Jacksonville, FL-based Crowley Maritime, says fresh produce importers face the added challenge of inspections.
“I don’t think there are enough people to be able to provide the service that the government requires in terms of inspections, fumigations and things like that,” she says. “The way we perform our inspections, they give us an appointment and we don’t place the cargo at the USDA inspection dock unless they are ready.
“At least with us, the cargo does not suffer any deviation of temperature until the inspection takes place,” says Ramos, whose company recently made substantial investments in a wireless asset monitoring system to improve transparency and temperature control.
And it’s not just temperature control that’s extending shelf life either.
Anders Holm, global head of sales and marketing for Copenhagen-headquartered Maersk Container Industry (MCI), explains controlled-atmosphere (CA) technology has broadened the horizons for fragile crops to travel further and last longer.
“In the beginning we focused on high respiring fruit, like bananas and avocado,” he says. “But in recent years we have also focused on high-value fruit like blueberries, for example, and lychees, where we have a specific service that helps to prepare the container with curtains and we flush with nitrogen and CO2.”
“So you have the optimum atmosphere for blueberries, for example, and you can transport them to the other side of the globe,” he says. “We log temperatures and the humidity but also the CO2 and the O2, and we will be able to transmit this information via our connectivity systems.”