molds vary depending on species. The newer
mixed peroxy acids are more effective than
the original peroxyacetic acid types on yeasts
and molds.
Mixed Peroxy Acid/Organic Acid
Sanitizers
The mixed proxy acid/organic acid com-
pounds are the next generation of proxy
acid-based sanitizers (Anon., 2003). This
composition is based on the synergistic
combination of organic acids and the origi-
nal peroxyacetic acid. Generally, these prod-
ucts have the same advantages and
disadvantages as the basic peroxy acid com-
pounds. Among them are: (1) effective over
a broad pH range; (2) effective against bac-
teria, yeasts, and molds; (3) satisfactory
activity in cold water; (4) affected minimally
by water hardness; and (5) less affected by
organic material than other sanitizers which
operate via an oxidative mechanism, such as
chlorine.
The mixed peroxy acid/organic acid sani-
tizers are generally more effective against
various yeasts and molds than the basic per-
oxy acids. They may be incorporated at
lower use levels than conventional basic per-
oxy acid compounds, producing the same
efficacy, but resulting in a lower concentra-
tion. These sanitizers have higher acidity
than basic peroxy acid compounds and are
more effective at combining sanitizing with
an acid rinse, which reduces mineral film
build-up. Also, they contain a surfactant that
reduces surface tension, thus, improved wet-
ting of the treated surface. An antimicrobial
in use in meat and poultry plants is a combi-
nation of sodium chlorite and citric acid
(Stahl, 2004).
Acid Anionic Sanitizers
These sanitizers are formulated with:
●anionic surfactants (negatively charged)●acids
phosphoric acid
organic acids
Acid anionic sanitizers act rapidly and kill
a broad spectrum of bacteria and have good
bacteriophage activity. They have good sta-
bility, minimal odor, are nonstaining, effec-
tive in a wide temperature range, and are not
affected by water hardness. An acidified
rinse can be combined with the sanitizing
step and removes and controls mineral films.
These sanitizers can be corrosive to unpro-
tected metals and a skin irritant, inactivated
by cationic surfactants, may foam too much
for CIP equipment, are less effective at a
higher pH, have limited and varied antimi-
crobial activity (including poor yeast and
mold activity), and are more expensive than
are the halogen sanitizers. The antimicrobial
effect of acid anionics appears to be through
reaction of the surfactant, with positively
charged bacteria by ionic attraction to pene-
trate cell walls and disrupt cellular function.
Increased interest in peroxyacetic acidhas
developed in CIP sanitizing for dairy, bever-
age, and food-processing plants. This sani-
tizer, which provides a rapid, broad-spectrum
kill, works on the oxidation principle through
the reaction with the components of cell mem-
branes. It reduces pitting of equipment sur-
faces by being less corrosive than are iodine
and chlorine sanitizers. Peroxyacetic acid can
be applied during an acidified rinse cycle to
reduce effluent discharge; it is also biodegrad-
able. Because this sanitizer is effective against
yeasts—such as Candida,Saccharomyces, and
Hansenula, and molds—such as Penicillium,
Aspergillus,Mucor, and Geotrichum, it has
gained acceptance in the soft drink and
brewing industry. Peroxyacetic acid is effec-
tive for sanitizing aluminum beer kegs.
Increased use of this sanitizer in dairy and
food-processing plants is attributable to its
efficacy against various strains of Listeria