Canned Products and Pâté 343maximum for bacterial growth destroy all
viable cells; however, spores may survive in
this condition.
In food - processing operations, the term
“ sterilization ” is incorrect, as sterility is not
fully achieved. This means that, although all
pathogens are destroyed, some nonpathogens
can survive, although environmental condi-
tions are such that they cannot proliferate.
Under this situation, it is said that foods are
“ commercially sterile, ” “ microbiologically
inactive, ” or “ partially sterile. ”
There are two methods of commercial
sterilization: placing the food in a container,
with further heating; or heating and cooling
the foods, then placing it in a container. The
fi rst method is the conventional canning
operation, developed by Appert in the eigh-
teenth century (therefore, it is also called
“ appertization ” ). The second method is called
aseptic processing.
In aseptic processing, the food is com-
mercially sterilized before packaging; it is
based on the same principles as pasteuriza-
tion, although the process is more severe. As
the temperature applied is between 132 ° and
175 ° C, this process is similar to HTST. It is
mainly based on enzyme inactivation, rather
than microbial destruction. Once the con-
tainer is fi lled with the food, a hot fl uid such
as brine is injected and the container sealed.
This method is effi cient only if further refrig-
eration is applied (Thumel 1995 ).Canning
Canning processing consists of fi ve stages:
(1) food preparation (cleaning, cutting, selec-
tion, etc); (2) can, pouch, or jar fi lling; (3) air
exhaustion; (4) sealing; and (5) thermal
processing (heating and cooling).Food Preparation
In the case of meat and meat products, the
earlier operations depend on the type of
product. Canned sausages are fabricatedcase, F must be between 12 and 15. This type
of preserves is intended for regions with
extreme heat and humid weather, such as the
humid tropics, with no other preservation
facility. Total F - value for the heating phase
is 9.4589, and for the cooling is 5.1602; the
overall value is F = 14.6191.
Commercial Sterilization
The general principles underlying heat -
transfer mechanisms and the response of
foods to the caloric fl ow are the same for all
processes. However, specifi c thermal pro-
cesses have particular objectives. The objec-
tive of cooking (roasting, grilling, boiling,
and steaming) and frying is mostly to destroy
heat - sensitive organisms and toxins, to
improve sensory characteristics, and to make
the product more digestable; it is carried out
at around 85 ° C, although frying can be done
at 160 ° to 190 ° C. Scalding is applied in order
to inactivate enzymes, remove gas trapped in
the tissues, and clean the food material; it is
carried out at around 65 ° C. Pasteurization
destroys only part of the vegetative cell pop-
ulations; therefore, further preservation
methods must be applied. In most cases, the
objective of pasteurization is to destroy
pathogens, as is the case with milk. The high -
temperature, short - time (HTST) pasteuriza-
tion method involves temperatures around
70 ° to 73 ° C for 15 to 20 seconds, or 140 ° to
150 ° C for 1 to 45 seconds for fl uid milk,
whereas in the low - temperature, long - time
method, heating is at 62 ° C for 30 minutes
(for fl uid milk).
Aseptic Processing
Sterilization is a process where severe treat-
ments are applied to completely destroy C.
botulinum or C. perfringens ; although it
results in a stable food, sensory characteris-
tics such as texture and fl avor are consider-
ably altered. A sterile food is that where
no viable microorganisms are present. How-
ever, treatments at temperatures above the