Posts Tagged “CO2”
While studies have shown transporting strawberries and some other produce items in a modified atmosphere extends the quality and lifespan of the items, how safe are these food items to eat that have been exposed to carbon dioxide (CO2) for nearly a week?
Rich Macleod, a scientist and basically the manager of the pallet divison for Transfresh Corp. feels this is a reasonable question for people to ask.
“The use of carbon dioxide in the handling of perishables is incredibally common,” Macleod states. He points to the use of CO2 in soda, which are the bubbles you see.
As for TransFresh, Macleod says the Organic Material Research Institute has certified the Tectrol application as organic. “So we are certified for use as an organic product,” he states. “The impact of CO2 in terms of maintaining the quality of the product….using a gas we breath in the environment, is an excellent trade off for what you get for enjoying more strawberries.”
As previously reported in this series, using the pallet covered system, Tectrol (CO2), results in less decay in strawberries (see chart).
Macleod, who started out as a lab assistant with a masters degree in post harvest science, sees the next step in research being to define what CO2 does for the nutrient value of strawberries. Such a study has never been done, he notes. He is hopeful such research will take place within the next five years.
While Tectrol’s primary use is with strawberries, it also is used with raspberries, blueberries and other items.
However, it also is found in containers on shipments by boat with items such as avocados, asparagus, and stone fruit for both imports and exports that are in transit eight to 10 days.
“Your cut salads are all cousins to the wrapped pallet program (with modified atmospheres). In fact, the cut salad program preceeded the pallet covered program,” Macleod says.
(This is Part 5 0f 6, 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.)
(Note: This was originally planned as a five-part series, but is now turning into a 6-part series as I keep finding more information that is not only interesting, but I believe can be of great value to you as a produce trucker. Also, the latest strawberry purchase at my local Wal-Mart, was again this season, a frustrating experience. While the berries had good color protected in the clamshell container, they turned out to be soft and spongy once I got home and opened it.
Part IV of this series, may provide a clue why my strawberry purchase was disappointing, and why your delivery of some strawberries, may be cost you a claim or rejection at destination. — Bill Martin)
For example, several produce shippers of fresh strawberries choose to use a non-sealed bag type system, according to Rich Macleod of TransFresh Corp., Salinas, CA, whose product is Tectrol.
In this series, I have used information from a study by the University of California, Davis/University of Florida study showing the advantages for truckers who have strawberry loads with palletized sealed bags using carbon dioxide (CO2). The study also is quite favorable to TransFresh. I’m referring to the research, Comparison of Pallet Cover Systems to Maintain Strawberry fruit Quality During Transit.
If I had not known Rich Macleod for years, being familar with his work, his concern for produce truckers and in general his honesty and integrity, plus his impressive career, I might be a bit wary of a study conducted in part by his alma mater, UC Davis, that is favorable to his company.
However, there was another study commissioned by PEAKfresh, a competitor of TransFresh. It was conducted by the Horticulture and crop Science Department at Cal Poly State University, San Luis Obispo, entitled, Comparison of the Efficacy of the PEAKfresh and Tectrol Systems for Maintaining Strawberry Quality.
This study can be found on both the PEAKfresh and TransFresh websites.
In part the research states, “Berries in PEAKfresh treated pallets became softer on average than berreis in the Tectrol treated pallets during cross-country shipments, and this is in agreement with previous research on the effect of elevated CO2 on strawberry firmness.”
Additionally the PEAKfresh commissioned study notes after a two-day shelf life, fruit from the Tectrol pallet system exhibited significantly less decay, from 3% to 7% than other systems evaluated.
So if research is showing that non-sealed pallet/bag systems results in more softness and decay in strawberries, why doesn’t everyone use the sealed system?
Rich Macleod says, “There is a significant price difference between an unsealed bag and a sealed MAP system (Tectrol). Obviously there is a lot more sophistication in materials, equipment and man power to create a sealed MAP.”
Macleod has been told the open bag systems cost around $8 to $12-plus per bag, while Tectrol charges its shippers $19.25 per service.
“Prices can range from $24/pallet to $30/pallet for either bag or service,” Macleod says.
Continuing, he states, “First off, if you are using the open bag system, you are not injecting any CO2. If you are using MAP (Tectrol), you not only are injecting CO2 or other gasses, you are trying to keep those gasses contained or sealed inside the system.”
Thus, Macleod wants the Tectrol CO2 levels to hit between 10% and 18% inside the sealed Tectrol bag upon arrival at destination. Thus, this process requires more material, specialized bags, sealing tape, CO2 injection machinery, etc.
So for obvious reasons, the Tectrol process costs a shipper more money, and apparently some shippers would rather risk strawberry quality shipped to customers, than pay more.
The old saying, “you pay for what you get” certainly seems to apply to modified atmosphere shipments of strawberries.
“Shippers who recommend and sell open bags enjoy a significant cost advatange over those recommending and selling a MAP like Tectrol. However, as a retailer, given the UC Davis data, why would you pay the same for an open bag service as a true MAP service,” Macleod asks.
And I, as a consumer, am wondering if Wal-Mart or their suppliers are not trying to cut corners on what they pay for strawberries because those berries are trucked across country in unsealed bags. It is the peak strawberry season, and I can’t seem to buy any decent strawberries!
(This is Part 4 0f 6 featuring an interview with Rich Macleod, vice president, pallet division North America for TransFresh Corp., Salinas, CA. He has been with the company since 1976, and has a masters degree in post harvest science from the University of California, Davis.)
The study was conducted by the University of California, Davis and The University of Florida.
While a primary goal of the study is to find better ways to have produce with better quality and flavor delivered from the field to the kitchen shelf, transportation plays a key role in this.
Rich Macleod of TransFresh Corp. describes this as a “global process” where it must be considered that actions taken during the entire handling process can influence even the best varieties of product that end up in the hands of the consumer.
“The study confirms my private belief, plus our private research over the years,” he says. “If you do these processes correctly; cool it, transport correctly with good temperature control, with a CO2 atmosphere, you are going to deliver better fruit to the consumer.”
In the report, it details strawberry shipments with palletized loads covered with bags and carbon dioxide (CO2). The transcontential shipments compared the modified atmosphere shipments of CO2 West, PEAKfresh, PrimePro and Tectrol (TransFresh).
The results of the study may show why Tectrol is the dominant supplier of bagged, controlled atmosphere shipments out of California. Macleod says over half of the California harvested strawberries in California are shipped using the Tectrol process by TransFresh. California also grows and ships the vast majority of the nation’s strawberries.
The summary of the study’s findings probably explains why many strawberries look great when shipped and still are beautiful when displayed in your local supermarket. However, how many times have you purchased strawberries in the store and no sooner get home and notice quality problems occuring (a common experience with yours truely, the purveyor of this website)?
The study summarizes, “The Tectrol cover was sealed to the pallet base, a partial vacuum was applied, and pressurized CO2 gas was injected inside….CO2 concentrations within pallets at the beginning and end of transport were higher (11% to 16%) in the sealed Tectrol system and relatively low (.06% to .30% in the open CO2 West, PEAKfresh and PrimePro cover systems.”
Continuing, the report states, “The incident of fruit decay was low (1% to 1.4%) after transport, but increased substantially following a 2-day shelf life at 68 degrees. However, fruit from the Tectrol pallets exhibited significantly less decay (36%) after shelf life than the CO2 West (39%), non covered (pallets)(41%), PrimePro (42%) and PEAKfresh (43%).”
(This is Part 3 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.)
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.)
Overall this season, I’ve been disappointed in the quality of California strawberries, both in taste and appearance. As long as your receiver knows what they are having delivered, then it should reduce your chances of claims or rejections. Hopefully quality will improve with the transition to northern shipping areas.
Studies have shown if your load has pallets with sealed bags from Tectrol with the CO2 modified atmosphere, you will have berries with better arrivals and extended shelf life.
California has refined growing methods on more than 40,000 acres and have improved yields by 44 percent since 1990, but you can’t control Mother Nature. About 90 percent of USA grown fresh strawberries are from California.
The Salinas/Watsonville district is easily the state’s most important when it comes to strawberry shipments, with loads amounting to nearly half of California’s production.
During a year, Salinas/Watsonville ships nearly 20,000 truck load equivalents of strawberries, with the Santa Maria district moving nearly 11,000 truck load equivalents and Southern Californa shipping over 12,000 truck load equivalents.
Although a few California growers began harvesting and shipping early blueberry varieties last March, the bulk of loadings occur in May and June, with the season ending by July.
California is now shipping blueberries and all the signs point to good volume and quality. The Golden state this year is expected to exceed the 1,100 truck load equivalents of “blues” shipped in 2012.
California is home to 80 blueberry producers and 20 handlers, and ranks fifth nationally blueberry shipments.
Blueberry volume is light, but seasonally increasing from the southern and central disticts of California. Raspberries are in light volume from Ventura County.
Salinas strawberries and vegetables – grossing about $7500 to New York City.