●Resistant to corrosion of metals and not
affected by hard water
●Stable against temperature fluctuation
with a long shelf life
●Nonirritating to the skin
●Effective at a high pH with detergency
and soil penetration ability
●Effective against mold growth
●Nontoxic
●Good surfactants that provide a residual
antimicrobial film
They have these disadvantages:
●Limited effectiveness (including ineffec-
tiveness against most gram-negative
microorganisms except Salmonellaand
E. coli) with low hard-water tolerance
and low-temperature activity
●Less effectiveness against bacteriophage
●Incompatibility with soaps and anionic-
type synthetic detergents since they are
cationic molecules
●Film forming on food-handling and
food-processing equipment
●Excessive foaming in mechanical appli-
cations and not recommended for use as
cleaning-in-place sanitizersAcid Sanitizers
Acid sanitizers, which are considered to be
toxicologically safe and biologically active,
are frequently used to combine the rinsing
and sanitizing steps. Organic acids, such as
acetic, peroxyacetic, lactic, propionic, and
formic acid, are most frequently used. Perox-
yacetic acid compounds acetic acid, octanoic
acid, and water, and are used at such low
concentrations that there is no residual vine-
gar flavor. The acid neutralizes excess alka-
linity that remains from the cleaning
compound, prevents formation of alkaline
deposits, and sanitizes. Because bacteria
have a positive surface charge, and negatively
charged surfactants react with positively
charged bacteria, their cell walls are pene-
trated, and cellular function is disrupted.
These sanitizers destroy microbes by pene-
trating and disrupting the cell membranes,
then dissociating the acid molecule and, con-
sequently, acidifying the cell interior. Acid
treatment is dose-dependent for spoilage and
pathogenic microorganisms. These com-
pounds are especially effective on stainless
steel surfaces or where contact time may be
extended and have a high antimicrobial activ-
ity against psychrotrophic microorganisms.
The development of automated cleaning
systems in food plants, where it is desirable
to combine sanitizing with the final rinse,
has made the use of acid sanitizers desirable.
After the final rinse, the equipment may be
closed to avoid contamination and held
overnight with no danger of corrosion.
Although these compounds are sensitive to
pH change, they are less prone to be affected
by hard water than are the iodines. In the
past, the disadvantage of these synthetic
detergents in automated cleaning systems
was foam development, which made it diffi-
cult to get good drainage of the sanitizer
from the equipment. Nonfoaming acid syn-
thetic detergent sanitizers have become avail-
able, eliminating this problem and making
these compounds even more valuable in the
food industry. These sanitizers are less effec-
tive with an increase in pH or against ther-
moduric organisms. Acids are not as efficient
as irradiation and, when applied at high con-
centrations, can cause slight discoloration
and odor on food surfaces, such as meat. The
cost effectiveness of acid sanitizers has not
been evaluated sufficiently, and experiments
with acetic acid have revealed a lack of effec-
tiveness in the reduction of Salmonella
species contamination.
Acid sanitizers are fast acting and effective
against yeasts and viruses. The pH range of
below 3 is the most ideal for the performance
of acid sanitizers. Acid anionic sanitizers
may be incorporated as an acid rinse for