equipment to leave it stainless, bright, and
shiny. These sanitizers have very good wet-
ting properties, are nonstaining and usually
noncorrosive, permitting exposure to equip-
ment overnight. Hard water and residual
organic matter do not have a major effect on
the effectiveness of acid anionic sanitizers
and they can be applied by cleaning-in-place
methods or by spray, or they can be foamed
on if a foam additive is incorporated. Acid
sanitizers can lose all of their effectiveness by
the presence of alkaline residuals or by the
presence of cationic surfactants. Bacterial
tolerance may increase on exposure of them
to moderate concentrations of acids (Mar-
shall, 2003). All cleaning compounds should
be rinsed from surfaces before acid sanitizers
are applied.
Carboxylic acid sanitizers (also known as
fatty acid sanitizers) are effective over a
broad range of bactericidal activity. They are
low foaming and can be used in mechanical
or CIP applications. They are stable in dilu-
tions, in the presence of organic matter, and
at high temperatures. These sanitizers are
noncorrosive to stainless steel, provide a
good shelf life, are cost effective and act as a
sanitizer and acid rinse. Carboxylic acid is
less effective against yeasts and molds and
not as effective above pH 3.4 to 4.0 as some
chemical sanitizers. They are negatively
affected by cationic surfactants, so thorough
rinsing of detergents is essential. This sani-
tizer is corrosive to nonstainless steels, plas-
tics, and some rubbers. Fatty acid sanitizers
may be composed of free fatty acids, sul-
fonated fatty acids, and other organic acids.
These sanitizers generally contain a mineral
acid, with phosphoric being preferred
(Anon, 2003). They are EPA registered as
no-rinse food-contact surface sanitizers and
act as a sanitizer and acid rinse. These sani-
tizers lack effectiveness at 10°C or lower.
Organic acids and bacteriocins offer poten-
tial as decontaminants. The effectiveness of
organic acids in reducing populations of
meatborne pathogens varies with the concen-
tration of acid used, temperature of the acid
and the carcass, contact time, spray applica-
tion pressure, point at which the sanitizer is
applied, tissue type, and the sensitivity of the
target organisms to the specific acid (Bar-
boza et al., 2002). The antibacterial effects of
lactic acid and acid mixtures (acetic acid with
lactic or propionic acid) against gram-nega-
tive organisms are generally more extensive
than their effects against gram-positive
microorganisms.Peroxy Acid Sanitizers
The peroxy acid-hydrogen peroxide sani-
tizers represent a newer class of sanitizers,
although they have been used extensively in
Europe since the 1970s. Peroxy acid is a
strong, fast-acting sanitizer that works on
the same basis as chlorine-based sanitizers,
through oxidation. It is EPA registered as a
no-rinse food-contact surface sanitizer at the
use dilution specified on the label. This sani-
tizer appears to be one of the most effective
of those compounds available for protection
against biofilms.
The low foam characteristics of the sani-
tizers, like chlorine, make them suitable for
CIP applications. They offer a broad range
of temperature activity, down to 4°C. As
acid-type sanitizers, they combine sanitizing
and acid rinse in one step. They leave no
residues and are generally noncorrosive to
stainless steel and aluminum in normal sur-
face applications. Furthermore, they are rel-
atively tolerant of organic soil.
Disadvantages of the sanitizers include
loss of effectiveness in the presence of some
metals contained in water. They are corro-
sive to some metals such as mild steel and
galvanized steel and high temperatures will
accelerate the corrosion rate. Full strength
proxy acid sanitizers have a strong, pungent
smell. Their effectiveness against yeasts andSanitizers 179