Principles of Food Sanitation

specific for any pathogen within a few minutes
with no special equipment and skills. It
detects pathogenic microorganisms based on
their nucleic acid sequences. Although the lat-
eral flow assay appears to be a technology
that is ready for commercialization, more
development is currently needed for the bio-
analytical microsystem.

Rapid Method Selection

A laboratory should evaluate the needs
and determine current level of knowledge
and instrumentation, and what is being
analyzed. If a large number of samples will
be evaluated consistently, the speed and costs
of supplies and labor may justify an invest-
ment in automated instrumentation.
An extensive amount of effort and money
has been devoted to the development of
instantaneous or real-time pathogen detec-
tion techniques. It is possible to reveal plant
sanitation levels quickly and to incorporate
these measurements to set high standards for
the involved plant. However, until more
sophisticated technology is available, a
pathogen-free status cannot be attained.
Even though improved technology may not
provide a pathogen-free environment, com-
plementary strategies will contribute to
improved hygiene.

Summary.................................................................................................

The role of microorganisms in food
spoilage and foodborne illness must be under-
stood if effective sanitation is to be practiced.
Microorganisms cause food spoilage through
degradation of appearance and flavor, and
foodborne illnesses occur through the inges-
tion of food containing microorganisms or
toxins which is a cause of concern for public
health. Microbiology is the science of micro-
scopic forms of life. Control of microbial load

from equipment, plants, and foods is part of a

sanitation program.

Microorganisms have a growth pattern

similar to a bell curve and tend to proliferate

and die at a logarithmic rate. Extrinsic fac-

tors that have the greatest effect on microbial

growth kinetics are temperature, oxygen

availability, and relative humidity. Intrinsic

factors that affect growth rate most are Aw

and pH levels, oxidation–reduction poten-

tial, nutrient requirements, and presence of

inhibitory substances.

Chemical changes from microbial degra-

dation occur primarily through enzymes, pro-

duced by microorganisms, which degrade

proteins, lipids, carbohydrates, and other

complex molecules into simpler compounds.

Foodborne illness may result from microor-

ganisms such as S. aureus, Salmonellaand

Campylobacterspecies,C. perfringens,C. bot-

ulinum,L. monocytogenes,Y. enterocolitica,

and mycotoxins.

The most common methods of microbial

destruction are heat, chemicals, and irradia-

tion; whereas, the most common methods

for inhibiting microbial growth are refrigera-

tion, dehydration, and fermentation. Micro-

bial load and taxonomy are frequently

assessed as measurements of the effective-

ness of a sanitation program by the various

tests and diagnoses that were discussed in

this chapter.

Study questions

1. What is the difference between a
   microorganism and a bacterium?


2. What is a virus?


3. How does contamination affect the lag
   phase of the microbial growth curve?


4. What is a psychrotroph?


5. What is Aw?


6. What is a biofilm?

The Relationship of Microorganisms to Sanitation 67