Del. State featuring refrigerated trailer

Staff Writer

SMYRNA, Del. (April 19, 2016) — When a farmer he’d been helping with a mushroom project lost 500 pounds of harvested mushrooms overnight due to heat in 2014, Dr. Lekha Paudel, farm management specialist at Delaware State University, looked for a way to prevent another such loss.
That’s when he contacted Dr. Penelope Perkins-Veazie, professor at North Carolina State University and postharvest physiologist at NCSU’s Plants for Human Health Institute.
As a result, Delaware State University has a “Cool It Now Mobile Farm Food Safety Unit” that was unveiled at a workshop April 13 in Smyrna.
The refrigerated trailer is based on a new mobile cooling unit developed at the Plants for Human Health Institute, called the “Pack N Cool.” Combining the mobility of a cargo trailer with the refrigeration capabilities of a commercial cooler, the Pack N Cool is designed to keep fruits and vegetables at ideal temperatures during transport to and from farmers’ markets or as they’re harvested in farm fields.
Construction for the Pack N Cool was spearheaded by Louis Wojciechowski, a lab technician with Perkins-Veazie’s research team. Using a new cargo trailer priced at $1,500, the first model unit, measuring 5 feet by 8 feet, cost about $3,500 to construct, not counting labor. Perkins-Veazie estimated paid labor might add another $2,000. THe next model was 6 feet by 10 feet. Construction guidelines, step-by-step photos and a sample budget are available online at
Paudel was able to get financial support to build DSU’s unit from a Specialty Crop Block Grant and a Capacity Building Grant offered to 1890 Land-Grant institutions through USDA’s National Institute of Food and Agriculture.
He is now working to educate farmers about this new method of keeping produce safe while prolonging shelf life of fruits and vegetables.
Delaware State University’s “Cool It Now” unit is equipped with a generator for field use, or can be plugged it. Builders here installed a longer tongue to accommodate the generator and moved the axle back to spread the weight.
The wooden interior was replaced by spray foam insulation and FDA-level plastic paneling. Diamond plating on the floor makes it more durable and easier to clean. The unit is high enough that Paudel can stand up in it; a taller visitor needed to tip his head a little.
The unit is big enough that a pallet will fit inside, and it could be outfitted with shelving. The insulated back doors open out and can be latched. Strips of heavy plastic could be added to the doorway to preserve the cool air.
Perkins-Veazie recommends that many fruits and vegetables be stored at 32 to 41 degrees F. as soon as possible after harvest. This includes most fruits (apple, blackberry, strawberry), leafy greens (cabbage, lettuce) and immature vegetables (broccoli, cucumber, green beans), which decay in heat.
Unfortunately, most standard air conditioners “bottom out” at about 60 degrees.
However, where there’s a will, there’s a way, and a farmer named Ron Khosia was determined to find a less expensive way to cool his harvest than a walk-in cooler.
He said he got the idea of making an air conditioner function as a cooler from the USDA, which had come up with a way to hardwire a high amperage timer onto an air conditioner compressor and add “heat tape” to the fins of the air condition to keep it from freezing up. It worked — but sometimes too well, resulting in a frozen air conditioner and spoiled vegetables. Khosia went back to the drawing board with a former college roommate, a Cornell engineer, who helped develop a micro-controller brain with multiple sensors to control the temperature. In the last 10 years, Khosia has sold 25,000 of these brains, called “CoolBot.” (For more information, visit
Perkins-Veazie said CoolBots sell for about $300, and a window air conditioner is about the same, inexpensive enough that if there’s a problem you can replace it rather than wait for a repairman.
The technology is used by florists, hunters, and micro-breweries to cool spaces up to 8 feet by 10 feet.
She added that the Pack N Cool or Cool It Now will stay cool until it’s turned off, making it possible to harvest in the afternoon and keep the produce fresh until morning, rather than bringing in a crew to harvest at 5 a.m. for marketing the same day.
Before opening the Cool It Now unit for inspection at the workshop, Perkins-Veazie discussed postharvest quality for fresh fruits and vegetables. Postharvest is a broad area, she said, beginning with harvest on the farm and ending with the consumer or final market. It is critical to consider sanitation, cleanliness and refrigeration, she said.
Don’t forget that plants — and fruits and vegetables — stay alive after harvest. But the crop begins to deteriorate the moment it is separated from its parent plant.
Key steps to care are to start with good quality, keep your product clean, put it in the most suitable container, keep it at the right temperature and humidity and keep it cool, but not too cold.