Agriculture Reference
In-Depth Information
9
Aqueous Antimicrobial Treatments to
Improve Fresh and Fresh-Cut
Produce Safety
Joy Herdt and Hao Feng
Introduction
Most fresh produce is subjected to washing after harvest, and it is usually done by
processors using fl ume transport systems, batch tanks, or water sprays. The washing
of fresh produce is an important step for removing soil and debris, improving the
appearance of the commodity, lowering the produce's temperature, and limiting the
development of physiological changes. Washing also reduces the microbial load on
the surface of incoming produce, which impacts the product's quality, shelf life, and
safety. With increasing concerns about the safety of fresh and fresh-cut produce, the
latter benefi t of washing is becoming increasingly more important. In most cases,
antimicrobials are added to the washing systems to enhance the control of micro-
organisms that are found on the surface of incoming fresh produce.
Water alone will provide the basic objectives of washing; however, it is very
common for processors to recycle the wash water for conservation. Reusing wash
water increases the risk of spreading contamination, because water can remove patho-
gens from the surface of produce and then transfer microbial contaminants to other
batches of produce during subsequent washing processes. Proper sanitation of the
wash water is critical to prevent the transmission of pathogens or other bacteria from
the contaminated to uncontaminated produce. This requires diligent monitoring and
controlling efforts to ensure that proper levels of antimicrobial agents are maintained
in the recycled water. The washing step is critical to remove the level of contamination
from the surface of the produce to the maximum extent possible, and the antimicrobial
in the water eliminates the microorganism.
Antimicrobial treatments vary in their effectiveness based on the chemical, physi-
cal, and mechanical action applied during treatment. Parameters such as concentration,
time, temperature, pH, washing dynamics, soil load on the produce, buildup of organic
material in the wash water, target microorganism, how and where the microorganism
is attached to the produce surface, the level of microorganisms on the surface of the
produce, and the produce surface topography must be considered when optimizing the
washing system. It is the combination of these factors that determines the effi cacy of
an antimicrobial treatment in reducing microbial populations on the surface of produce.
Summarized in this chapter are several antimicrobial agents that have been cleared by
the FDA for washing fruits and vegetables.
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