Desiccant dries up
Del Monte damage
| Protecting primary packages from
condensation and moisture damage when shipping product halfway across the globe is no easy
feat. Pineapple canned at its source in the Philippines by San Francisco based Del Monte
Foods underwent lengthy, month-long voyages through extreme climates from tropical to
arctic before reaching U.S. and other destinations, mostly without incident. But in 1993
Mother Nature threw Del Monte a curve ball in the form of altered weather patterns, and
cans inside the overseas cargo containers began sustaining extensive moisture damage,
despite being packed in corrugated containers, stacked on pallets and unitized with
stretch wrap. "We found heavy amounts of rust on the cans, and discoloration of the
paper labels," says Terry Koberstein, principal packaging technologist for Del Monte.
"It was worse than anything we had seen before." Del
Monte quickly took steps to contain the damage. "We set up inspection procedures at
tremendous cost to ensure that our customers were getting the highest quality
product," recalls John Pearson, Del Monte's director of technical services and
development, and head of the packaging team that eventually solved the problem.
"Since we responded immediately after the problem was detected, only a few customers
witnessed it," he says. After experimenting with different solutions in simulated
weather conditions in high-tech, climate-controlled rooms at its Walnut Creek, Calif.,
R&D facility, the company found the most success with United Desiccants’
Container Dri® desiccant pouch. |
The desiccant was developed specifically
to combat condensation during long-haul transport via sea, air or land. The 500-g pouches, made from a clay-based desiccant, absorb up to half their
weight in moisture, unlike silica-gel desiccants that adsorb moisture, or attract moisture
only to the surface of the desiccant. While silica-gel
The can on the left above, was shipped
without the clay-based desiccant attached to pallet loads, below.
desiccants technically would have worked, the sheer quantities that
would be required were neither practical nor cost-effective. Container Dri activates
whenever the dew point is reached and condensation starts to form inside the cargo
container. The dew point |
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itself varies depending on a number of
factors including temperature and humidity. When product reaches its destination, the
pouches are removed and discarded. "You could feel the difference between Container
Dri and silica gel," says Janice Ma, a Del Monte researcher involved in the project.
"When you picked up the Container Dri, it was heavy, soaked with water, while the
silica gel hadn't absorbed nearly as much moisture." The
10x5 3/4x1-in. pouches are either laid on the floor of cargo containers or are taped at
intervals atop pallet loads as they are loaded inside. Seventeen pallets, with 100 cases
per pallet, are loaded into each sealed container; the same quantity of desiccant is used
each time. Cargo containers are loaded in Bugo (Philippines), shipped to Kaohsiung,
Taiwan, for transfer to a larger vessel (after storage time on the docks). Product enters
the U.S. via one of three ports: Seattle, Oakland or Los Angeles.
Del Monte reports an extremely high success rate in eliminating
moisture damage, resulting in savings that run into the millions of dollars, primarily
from recovered product and lower insurance premiums. Inspections are now limited to an
occasional monitoring of humidity via probes placed in an occasional cargo container.
Although the company began using the desiccant in April '94, "We waited a full year
before calling the program a success," says Koberstein, "to make sure we went
through every season and every factor that could occur in a 12-month cycle. Since using
Container Dri we've had a 100-percent success rate, zero failures and no damage claims.
"
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