Principles of Food Sanitation

metal paneling to enhance the ability to
clean inside walls. This material is resistant
to food, blood, acid, alkali, cleaning com-
pound, and sanitizer. Tile walls are expensive
to install but inexpensive and easy to main-
tain. Epoxy paints over a compatible sealer
provide additional protection.

Loading Dock

Loading docks and platforms should be
constructed at least 1 m above the ground.
The underside of the dock opening should
be lined with a smooth, impervious material,
such as plastic or galvanized metal, to pre-
vent rodents from climbing into the building.
Rodent access should be denied through a
dock or platform overhang of 30 cm that will
not permit a roosting location for birds. Pest
entry is discouraged through truck door
seals and air curtains.
The truck dock area should be equipped
with dock seals. This design prevents the
entrance of insects and if the plant is under
positive pressure with air flowing out of the
openings that do occur around the seal dust
contamination is reduced. Dock seals can
replace overhead canopies that require con-
stant monitoring to prevent pest entry, espe-
cially birds.

Roof Construction

A logical roof type for precast concrete
wall panels is a precast double tee. This
design is attractive and hygienic. Pitch and
gravel roofs should not be installed over food
processing or preparation areas, as they are
difficult to clean. Low-moisture materials,
such as grain, starch, and flour, can be car-
ried out through vents and will attract birds
and insects and encourage the growth of
weeds, bacteria, molds, and yeasts. Graham
(1991c) has recommended smooth mem-
brane-type roofs because they can be swept,
hosed, and kept clean more effectively than
other roofs. Roof openings for air handling

or other uses should be screened, flashed, or

sealed to prevent the entry of contaminants

such as insects, water, and dust. Roof open-

ing caps and mounted air-handling units

should be insulated with sandwich panel

insulation, as open insulation is difficult to

clean and can become infested with insects.

Windows

Effective environmental control and ade-

quate lighting negates the need for windows,

which can present a sanitation hazard, due

to breakage and contamination from pests,

dust, and other sources. Windows increase

maintenance through required repair, clean-

ing, and caulking. If windows are installed,

it is best if they cannot be opened and if they

are constructed of unbreakable polycarbon-

ate material (Graham, 1991c). Furthermore,

the sill on the outside should be sloped at a

60 ° angle to prevent roosting and debris

accumulation. The next best design for win-

dows is to place them flush with the outside

wall and to use the same slope for the inside

sill. Some municipalities require windows to

conform to local fire codes.

Doors

Doors provide an entry for pests and air-

borne contaminants. A double-door entry

reduces airborne and pest contamination.

The exterior of the doors should be

equipped with air curtains. Air curtains

should have enough air velocity (minimum

of 500 m/minute) to prevent the entry of

insects and air contaminants and should

extend completely across the opening with a

down-and-out sweep. Air curtains should be

wired directly into the door-opening switch

to permit air movement simultaneous with

the door opening and closing.

Ceilings

False ceilings are discouraged because the

area above can become infested with insects

Sanitary Design and Construction for Food Processing 259