Researchers used a probe to create a dielectric barrier discharge plasma and apply it to raw chicken. Image: Drexel University |
A new study by food safety researchers
at Drexel University demonstrates that plasma can
be an effective method for killing pathogens on uncooked poultry. The
proof-of-concept study was published in the Journal of Food Protection.
Although recent high-profile outbreaks
of foodborne illness have involved contaminated fresh produce, the most common
source of harmful bacteria in food is uncooked poultry and other meat products.
The bacteria responsible for most foodborne illnesses, Campylobacter and
Salmonella, are found on upwards of 70% of chicken meat tested.
Treating raw meat products to remove
pathogens before they reach a consumer’s home can reduce the risk of cross
contamination during food preparation, according to senior author Jennifer Quinlan, PhD,
an assistant professor in Drexel’s College
of Nursing and Health
Professions. “If you could reduce contamination on the raw chicken, then you
wouldn’t have it in the kitchen,” Quinlan said.
Past studies have shown that plasma
could successfully reduce pathogens on the surface of fruits and vegetables
without cooking them.
The value of using plasma “is that it
is non-thermal, so there is no heat to cook or alter the way the food looks,”
said lead author Brian Dirks, a
graduate student in the College
of Arts and Sciences.
Dirks and Quinlan worked with researchers from the University’s Anthony J.
Drexel Plasma Institute to test the use of plasma for poultry.
In the Drexel study, raw chicken
samples contaminated with Salmonella enterica and Campylobacter
jejuni bacteria were treated with plasma for varying periods of time.
Plasma treatment eliminated or nearly eliminated bacteria in low levels from
skinless chicken breast and chicken skin, and significantly reduced the level
of bacteria when contamination levels were high.
The researchers also tested using
plasma to treat samples of bacteria grown on agar, and demonstrated that
antibiotic-resistant strains of bacteria were as susceptible to plasma as the
wild-type strains.
Plasma, known as the “fourth state of
matter” (after solid, liquid and gas), is a high-energy, charged mixture of
gaseous atoms, ions, and electrons. Plasma has a wide range of potential
applications including energy production and control, biomedical treatments,
and environmental remediation.
Quinlan described the plasma treatment
of poultry in this study as “proof of concept.” Current plasma technology is
expensive relative to the narrow cost margins involved in food production, and
the technology is not currently being developed for processing poultry on a
large scale.
If plasma technology becomes
cost-effective for use in treating poultry, it may be used in conjunction with
existing methods to reduce pathogens, Dirks said, and it may also help prolong
the shelf-life of raw chicken if it can be honed to remove more microorganisms
responsible for spoilage.
“Until
these technologies are more fully developed, consumers should assume that raw
poultry has pathogens on it and take care to prevent infection,” Quinlan said. “That means cooking thoroughly and making sure not to cross contaminate when
handling uncooked meat and poultry.”
