Bacteria are everywhere - in the air, in the water,
in the ground, on our food, on our skin, inside our bodies. Scientists have
various ways of classifying and describing these bacteria. As food workers, we
are interested in a way of classifying them that may be less scientific but is
more practical to our work.
1. Harmless bacteria = Most bacteria fall into this
category. They are neither helpful nor harmful to us. We are not concerned with
them in food sanitation.
2. Beneficial bacteria = These bacteria are helpful
to us. For example, many live in the intestinal tract, where they fight harmful
bacteria, aid the digestion of food, and produce certain nutrients. In food
production, bacteria make possible the manufacture of many foods, including cheese,
yogurt, and sauerkraut.
3. Undesirable bacteria = These are the bacteria
that are responsible for food spoilage. They cause souring, putrefying, and
decomposition. These bacteria may or may not cause disease, but they offer a
built-in safety factor: They announce their presence by means of sour odors,
sticky or slimy surfaces, and discoloration. As long as we use common sense and
follow the rule that says “when in doubt, throw it out,” we are relatively safe
from these bacteria.
We are concerned with these bacteria for two
reasons:
•
Food spoilage costs money.
•
Food spoilage is a sign of improper food handling and storage.
This means the
next kind of bacteria is probably present.
4. Disease-causing bacteria, or pathogens = These
are the bacteria that cause most food-borne illness, the bacteria we are most concerned
with. Pathogens do not necessarily leave detectable odors or tastes in food. In
other words, you can’t tell if food is contaminated by smelling, tasting, or
looking at it. The only way to protect food against pathogenic bacteria is to
use proper hygiene and sanitary food handling and storage techniques.
Each kind of bacterial pathogen causes disease in
one of three ways:
1. Intoxications are caused by poisons (toxins) the
bacteria produce while they are growing in the food. It is these poisons, not
the bacteria themselves, that cause the diseases.
2. Infections are caused by bacteria (or other
organisms) that get into the intestinal system and attack the body. Disease is
caused by the bacteria as they multiply in the body.
3. Toxin-mediated infections are also caused by
bacteria that get into the body and grow. Disease is caused by poisons the
bacteria produce as they grow and multiply. Most food-borne diseases are
toxin-mediated infections.
[source: professional cooking sixth edition]
