Food Protection Trends - March/April 2018 - 97

beef processing facility measured 470 l/1000 kg Live
Body Weight for intervention processes (14), which is a
refinement and reduction from prior reports of 570-1700
l water/animal (2). Although the mechanical action of
water can provide some removal of surface microbial
contamination that may naturally be present on the carcass,
the use of water alone introduces a food safety risk, as a
single carcass may cross-contaminate pathogenic bacteria to
uncontaminated carcasses being processed at the same time
or later (6).
This use of water relates directly to the importance
of critical control points in use at processing facilities
for organisms of public health significance. To control
both pathogenic and spoilage microorganisms naturally
present on the meat surface and decrease the presence of
microorganisms due to cross-contamination, the use of
an antimicrobial agent(s) in process water is common.
This method can achieve a reduction in microbial levels
by several orders of magnitude. Options available for
use in processing include oxidative chemicals, such as
hypochlorite, acidified sodium chlorite, bromine, or
peroxyacids; organic acids, such as lactic acid; and the
quaternary ammonium antiseptic cetylpyridinium chloride
(11). Information on the use of each type of antimicrobial
is lacking; however, the use of oxidative chlorinated
interventions has declined for various reasons. Restrictions
on meat or poultry processed with hypochlorite have
been in effect since 2010 for Russia, and a ban on the use
of pathogen reduction treatments other than water or
lactic acid has been in effect for the EU since 1997 (8).
Import/Export restrictions are continually revised and
subject to change, with the most recent list of approved or
disapproved agents permitted for United States exported
meat and poultry product use listed in the U.S. Department
of Agriculture Food Safety and Inspection Service (USDA
FSIS) Export Library (13).
Of the aforementioned options for microbial intervention,
peracetic acid has almost certainly increased in usage over
the past decade. Adoption and acceptance of its use is
attributable to several factors, including broad allowance by
beef and poultry importing countries, a large operating range
with efficacy at low levels, a high tolerance for organic load,
and the unique property, by comparison with the others,
of a breakdown path resulting in innocuous acetic acid (the
acid component of vinegar), water, and oxygen. The use of
peracetic acid thus falls in the category of a processing aid by
regulatory definition (12), exhibiting no ongoing technical or
functional effect in finished food products.
Along with the expanded use throughout the industry,
recent regulatory updates have approved the use of peracetic acid at levels ten times higher than that specified
in the original approval (e.g., FDA FCN 1495). Although
regulatory authorities agree that peracetic acid and hydrogen peroxide do not persist on meat and poultry, their rate

of degradation, which is the focus of the present study, has
not been published/studied. The study design was to treat
chicken and beef samples at a level of peracetic acid slightly
above the current allowable maximum level of 2000 ppm,
drain treated samples for incremental periods of time, and
then recover and measure the residual levels of peracetic
acid and hydrogen peroxide from the samples, allowing for
calculation of decay kinetics of both chemical species. In
addition to demonstrating the degradation of both species
on either meat type, this study provides a time estimate
of the zero-point residue levels for each chemical species
(peracetic acid or hydrogen peroxide) for each type of meat
tested. Such data are frequently used in the evaluation of
finished food product safety and meeting certain regulatory
authority requirements of negligible residue remaining on
product for processing aid qualification.
MATERIALS AND METHODS
Fresh, non-frozen chicken drums (with skin and bone)
and round steak samples were acquired at a local grocery
store and used within 48 hours of purchase. Samples were
stored at refrigerated temperatures until used. Chicken
drums were used as purchased, beef samples were cut
approximately in half, such that each chicken or beef sample
tested was in the range of 50-100 g. Commercial peracetic
acid (herein referred to as "commercial peracid") was used
for each of the studies, with nominal equilibration levels
of 15.2% peracetic acid and 11.2% hydrogen peroxide
(Ecolab Inc. St. Paul, MN). All dip water used in this study
was controlled at 5 grains per gallon hardness. Water was at
room temperature (20-22°C) at time of use.
Antimicrobial solution preparation
Peracetic acid (PAA) dip solution was prepared by
adding 10 kg of water to a clean, 20 l plastic pail, into which
the commercial peracid was added and thoroughly mixed.
The mixed solution was then analyzed using the suppressed
peroxide iodometric method (10) for peracid and peroxide
levels with 0.1 N thiosulfate titrant. The peracetic acid and
hydrogen peroxide levels of the dip/immersion solution
was verified before and after all testing to verify that the
concentration of peracetic acid was between 2000 and 2300
ppm. For each test of meat immersion, ~600 ml of a large
stock of immersion solution was added to a 1 l beaker, and
more was added if needed to fully submerge the chicken or
red meat sample. Immersion solutions were used once and
discarded, so that the nominal peracetic acid solution used
throughout the study was kept constant.
Meat preparation and antimicrobial application
Samples were manually placed into the peracetic acid
dip solutions and agitated for 30 s, after which time they
were aseptically removed with a plastic utensil and set on
a rubber-coated metal rack for the set drain times. Whirl-

March/April Food Protection Trends

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