and vegetable products, cheeses, salads, dips,
grains and grain products, and liquids includ-
ing juices, sauces, and soups. The high pres-
sure does not destroy the food, because it is
applied evenly from all sides. Microorgan-
isms living on the surface and in the interior
of the food are inactivated. Inactivation is
accomplished by affecting the molecular
structure of chemical compounds necessary
for metabolic metabolism in the microorgan-
isms. HHP is equally effective on molds, bac-
teria, viruses, and parasites, and has achieved
some success in treating bacterial spores,
which are resistant to many biocidal process-
ing treatments.
The decomposition of proteins and lipids
(which may result from enzymes of micro-
bial contamination) from many foods that
have active enzyme systems of their own
contribute to produce spoilage at refriger-
ated temperatures. HHP has resulted in the
inactivation of certain enzymes that result in
the deterioration of food.
Vacuum/Steam/Vacuum
A process (Kozempel, 2003) has been
developed that exposes solid food products
to vacuum, steam, and vacuum again (VSV).
Saturated steam is incorporated to capitalize
on the large latent heat of condensation rel-
ative to the sensible heat transferred due to
temperature difference in cooling super-
heated steam. Although the process has not
been fully explored at this time, it appears to
have potential for the destruction of patho-
genic microorganisms in fresh meat and
poultry, processed meats, seafood, and fruits
and vegetables.
Chemical Sanitizing
The chemical sanitizers available for use in
food processing and foodservice opera-
tions vary in chemical composition and
activity, depending on conditions. Generally,
the more concentrated a sanitizer, the more
rapid and effective its action. The individual
characteristics of each chemical sanitizer
must be known and understood so that the
most appropriate sanitizer for a specific san-
itizer application can be selected. Because
chemical sanitizers lack penetration ability,
microorganisms present in cracks, crevices,
pockets, and in mineral soils may not be
totally destroyed. For sanitizers to be effec-
tive when combined with cleaning com-
pounds, the temperature of the cleaning
solution should be 55°C or lower, and the
soil should be light. The efficacy of sanitizers
(especially chemical sanitizers) is affected by
physical–chemical factors such as:
Exposure time: Studies have suggested
that the death of a microbial population fol-
lows a logarithmic pattern, indicating that if
90% of a population is killed in a unit of
time, the next 90% of the remaining is
destroyed in the next unit of time, leaving
only 1% of the original number. Microbial
load and the population of cells having var-
ied susceptibility to the sanitizer due to age,
spore formation, and other physiological
factors determine the time required for the
sanitizer to be effective. The EPA registered
label for appropriate contact time should be
noted. When a sanitizer is applied via a cen-
tral sanitizer system or spray application,
which is generally used to sanitize exterior
equipment surfaces or for environmental sani-
tizing, it should be used at the maximum con-
centration permitted on the EPA product label
as a no-rinse food-contact surface sanitizer.
This approach is necessary to compensate for
inadequate manual cleaning-especially in dif-
ficult to clean areas and to compensate for
the natural dilution that may occur because
of the presence of condensation or residual
rinse water from cleaning.
Temperature: The growth rate of the
microorganisms and the death rate due to
chemical application will increase as temper-
ature elevates. A higher temperature generally