86 PRINCIPLES OFFOODSANITATION
Jewelry
To reduce safety hazards in an environ-
ment containing machinery, jewelry should
not be worn in food processing or foodservice
areas. Also, it may be contaminated and fall
into food.
Hair
Microorganisms (especially staphylococci)
are found on hair. Employees who scratch
their heads should use the hand dip before
handling food and should wear a head cover.
The necessity for wearing hair coverings in
food processing areas should be considered a
condition of employment for all new employ-
ees and should be made known at the time
when they are hired. Disposable hair covers
should be worn beneath hard hats. The use of
“overseas” type paper hats is not a good san-
itation practice as not all of the hair is
restrained.
Eyes
The eye itself is normally free of bacteria
but mild bacterial infections may develop.
Bacteria can then be found on the eyelashes
and at the indentation between the nose and
eye. By rubbing the eyes, the hands are con-
taminated.
Mouth
Many bacteria are found in the mouth and
on the lips. During a sneeze, some of the bac-
teria are transferred to the air and may land
on food being handled. Furthermore, smok-
ing should be prohibited while working. Var-
ious disease-causing bacteria, as well as
viruses, are also found in the mouth, espe-
cially if an employee is ill. These microorgan-
isms can be transmitted to other individuals,
as well as to food products, when one sneezes.
Spitting is usually prompted after smok-
ing, due to an irritating taste in the mouth or
when one has a head cold. This practice
should never be permitted in food processing
establishments. Spitting is unsightly and is a
mode of disease transmission and product
contamination. Brushing the teeth prevents
the buildup of bacterial plaque on the teeth
and reduces the degree of contamination
that might be transmitted to a food product
if an employee gets saliva on the hands or
sneezes.Nose, Nasopharynx, and Respiratory Tract
The nose and throat have a more limited
microbial population than does the mouth.
This is because of the body’s effective filter-
ing system. Particles larger than 7 μm in
diameter that are inhaled are retained in the
upper respiratory tract. This is accomplished
through the highly viscid mucus that consti-
tutes a continuous membrane overlying the
surfaces within the nose, sinuses, pharynx,
and esophagus. Approximately half of the
particles that are 3 μm or larger in diameter
are removed in the remaining tract, and the
rest penetrate the lungs. Those particles that
do penetrate and lodge themselves in the
bronchi and bronchioles are destroyed by the
body’s defenses. Viruses are controlled
through virus-inactivating agents found in
the normal serous fluid of the nose.
Occasionally, microorganisms do pene-
trate the mucous membranes and establish
themselves in the throat and respiratory
tract. Staphylococci, streptococci, and diph-
theroids are frequently found in these areas.
Other microorganisms occasionally inhabit
the tonsils. The common coldis one of the
most prevalent of all infectious diseases. It is
generally accepted that the common cold is
caused by rhinoviruses. The initial viral
attack is generally followed by the onset of a
secondary infection because the initial dis-
ease lowers the resistance of the mucous
membranes in the upper respiratory tract.