Baking & Snack - June 2015 - 104

INGREDIENT HANDLING

dust so there is no personnel exposure. When you go
into a new bakery now, they're really clean compared
with how they were in the past."
An effective preventive maintenance schedule often
involves monitoring filter media or checking bag houses
or cartridges for possible clogging or rupture, according
to James Toole, product manager, bulk handling systems,
Gemini Bakery Equipment/KB Systems, Philadelphia.
"Ensure that combustible ingredients are stored correctly
and properly maintained," he advised. "Train personnel
on proper handling and transferring of flammable ingre-

dients. Incorporate properly designed pneumatic systems
when conveying large quantities of dust-prone ingredients. Always repair any damaged equipment or correct
any equipment issues in a timely manner."
In addition to cleaning filters and monitoring flexible
and bolted connections, the filter systems' flexible connections and seals on storage bins need to be routinely
examined. "Those are your biggest contributors to combustible dust in a bakery's ingredient handling system,"
Mr. Stricker said.

Mounting a preventive defense

Keeping doughs without ice

Coles Quality Foods chills flour
from its outdoor silo as it flows
to the mixer with a dry ingredient
chilling system that uses liquid
carbon dioxide (CO2).
Linde LLC

Providing front-end control to the process is
critical to quality in many bakeries and food
manufacturing plants. Linde LLC, Murray
Hill, NJ, helped Coles Quality Foods' facility
in North Liberty, IA, improve consistency
of extrusion and finishing operations for
its twisted breadsticks and cheese sticks
through use of a cryogenic dry ingredient
chilling system.
A couple of years ago, Linde installed
the system over a three-day weekend. With
fully automated temperature monitoring
and control, the system also eliminated the
handling and worker safety issues associated with the use of ice, noted Ed Cordiano,
program manager, bakery and prepared
foods, at Linde.
Grand Rapids, MI-based Coles' products
have a one-year frozen shelf life. Cases are
shipped to national distribution centers and
sold throughout major supermarkets.

104 Baking & Snack June 2015 / www.bakingandsnack.com

Good housekeeping also requires preventing dust from
building up on equipment, pipes, the floor or even the ceiling so that even a small oven fire doesn't turn into a larger
disaster. Kevin Pecha, sales manager, AZO, Inc., Memphis,
TN, explained that dust clouds can develop as a result of
normal conveying or they can be generated through faulty
material handling, creating a potential condition to cause
such an explosion. "Secondary conflagrations can occur by allowing dust collecting on flat surfaces to become
airborne," he said. "Proper ventilation as well as diligent
sanitation, in conjunction with care to prevent electrical or
static discharges, should be of great importance."
In some cases, unsafe conditions in bakery ingredient
systems may result from poor initial design, misuse, inadequate maintenance and poor housekeeping, observed
Bill Kearns, vice-president of engineering, Fred D. Pfening
Co., Columbus, OH.
"Most dust explosions that reach the news have poor
housekeeping as one element," Mr. Kearns said. "Typically,
what happens is that a small primary event shakes loose
dust from building rafters and overhead pipes and provides an ignition source for a much larger secondary explosion. A good management plan includes preventing
both the primary event, by having proper equipment and
maintaining it, and with good housekeeping to avoid any
dust accumulations."
A deflagration event - which can be a fire or explosion - requires an ignition source, a confined space,
ample oxygen and flammable dust. Most bakery ingredients, such as flour, have fairly low combustibility. However, if the conditions are right - a light cloud
of fine dust could envelop the area - the risk is there.
That's especially true with the many ignition sources
present in a typical bakery, ranging from ovens and fryers to welding and static electricity.
"Virtually all organic bakery ingredients are combustible and thus carry varying degrees of fire and
explosion risk," Mr. Kearns said. "Non-organic ingredients, such as salt and calcium sulfate, are generally non-combustible and do not have similar risks. In
general, the more finely divided and drier the ingredi-

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