Fruit and Vegetable Processing Plant Sanitation 343Cleaning-in-Place (CIP)
With this closed system, a recirculating
cleaning solution is applied by nozzles that
automatically clean, rinse, and sanitize equip-
ment. However, this equipment is expensive
and ineffective on heavily soiled areas. Never-
theless, CIP cleaning has application in vac-
uum chambers, pumping and circulation
lines, and large storage tanks. Since most
fruits contain sugar and are low in fat con-
tent, water will flush most of the materials
away. An acid cleaner or rinse should be
incorporated to reduce scale buildup. Higher-
volume operations are better adapted to CIP
cleaning because labor savings provide a
quicker payout of the equipment. Additional
information about cleaning equipment is pro-
vided in Chapter 11.
Cleaners and sanitizers
Soil remaining on equipment or at any loca-
tion in the plant after cleaning is contami-
nated with microorganisms. Thorough
physical cleaning of all equipment and rooms
is necessary to prevent microorganisms from
contacting chemical sanitizers. (Readers are
referred to Chapter 9 for additional informa-
tion on cleaning compounds.) Residual soil
can also reduce the strength of chemical sani-
tizing solutions. Combination cleaners (deter-
gent–sanitizers) are used most frequently with
smaller operations that perform manual
cleaning at a temperature below 60°C. If the
cleaning medium temperature exceeds 80°C,
the solution will destroy spoilage microorgan-
isms and most pathogenic bacteria without
application of a chemical sanitizer.
Halogen Compounds
Chlorine and its compounds are the most
effective sanitizers of the halogens for sanitiz-
ing food processing equipment and contain-
ers, and for disinfecting water supplies.
Calcium hypochlorite and sodium hypochlo-
rite are two of the most frequently used sani-
tizers in fruit and vegetable processing plants.
Although elemental chlorine is less expensive
on an available chlorine basis, calcium
hypochlorite and sodium hypochlorite are eas-
ier to apply in low concentrations. Hypochlo-
rite solutions are sensitive to changes in
temperature, residual organic matter, and pH.
These compounds are quick acting and less
expensive than other halogens but tend to be
more corrosive and irritating to the skin.
Additional information about chlorine and
iodine sanitizers is provided in Chapter 10.Chlorine Dioxide
Chlorine dioxide is approved as a flume
water treatment for fruits and vegetables
(that are not raw agricultural commodities)
at a concentration of up to 3 ppm and to
control microorganisms in process waters.
Also, it is incorporated in wastewater treat-
ment and for slime control in cooling towers.
The typical use concentration of this sani-
tizer is 1 to 10 ppm (Anon., 2003).Quaternary Ammonium Compounds
Quaternary ammonium compounds
(“quats”) are effective against most bacteria
and molds. These compounds are stable as
a dry powder, a concentrated paste, or in
solution at room temperature. They are
heat stable, water soluble, colorless, odorless,
noncorrosive to common metals, and nonir-
ritating to the skin in normal concentrations.
These compounds are more active if soil is
present than are other sanitizers, and they
express the greatest antimicrobial activity in
the pH range of 6.0 and above. The quats
have limited bacterial effectiveness when
combined with cleaning compounds or when
dissolved in hard water.Acid Sanitizers
Peroxyacetic acid-based sanitizers provide
microbial control for use in fresh-cut, further