The lowly swab has long been a mainstay in the food safety pro- gram in most, if not all, food and beverage plants. The swab, as we know it today, began its journey as a small piece of cotton
wrapped into a bud at one end of a wood dowel. Clinicians around
the world used the swab to transfer small samples of tissue from
the human mouth, nose,
wounds, surgical sites, etc.
on the way to the microbiolo-
gy lab. Over time, food microbiolo-
gists and a handful of suppliers adopted
the clinical swab and made good use of
it in microbiological sampling on sur-
faces in the food plant.
The swab is very good for reach-
ing hard-to-sample crevices and
piping in the production line. These
crevices can be difficult to clean
and sanitize, frequently making
them critical sampling sites. The
swab itself evolved into
a flexible plastic rod
with a synthetic bud
ibility. The swab’s
relatively small size
cians to carry a
dozen or more
in a pocket.
However, the swab
continues to have some limita-
tions. The sample size is small and sam-
pling reproducibility is low (personal observation,
J. Zindulis, Ph.D., production manager, Weber Scientific). The swab
was not originally designed for quantitative use. As a result, people
have attempted to rectify this with a number of specified surface
area measurements and techniques. However, few technicians ap-
pear to enjoy the additional time spent to follow these procedures.
This further contributes to low reproducibility.
A viable alternative to the draconian use of the swab is the
sponge-on-a-stick. Although sponge samplers have been available
for some time, a few recent changes
have breathed new life into this concept.
One new design is the MegaSampler™
with a 4.5-sq. in. sponge on a stiff plastic
rod. This is housed in a sterile bag that
can easily be opened and closed. The
sponge contains Dey Engley (DE) neu-
tralizing buffer to stabilize the microbial
sample while simultaneously counteract-
ing many common cleaning agents and
sanitizers. The flat sponge is secured
to the sampling handle using a unique
design that enhances sampling efficacy
by having twice the sampling surface.
Also, the sponge itself extends over the
plastic handle, enabling the sponge to
move into difficult to reach areas. The
MegaSampler stick has a scraping blade
adjacent to the sponge, intended for
lifting biofilms. Since biofilms are no-
toriously difficult to sample, physically
scraping a surface may help access a
microbial population that a swab cannot.
When a MegaSampler is returned to its
bag, any debris on the scraper can be
brought down to the bottom of the bag,
and the sponge is easily removed from
the handle. At that point, a volume of DE
neutralizing buffer can be extracted from
the sponge and subsampled directly to
a plate or to another broth. The Mega-
Sampler also does an excellent job of
sampling both large and small surfaces,
either flat or curved, with minimal effort.
Minimal effort means that the device will
be used and used consistently. There
might also be a small fun factor, which
can only help the overall program.
Multiple publications have shown improved recovery of Listeria spp.,
Salmonella spp., and additional bacteria, using
sponges as compared to swabs. This is
not unexpected, simply based on the
increased surface area of the sponge and
the sponge’s ability to absorb material
from a surface wetted by the neutralizing
buffer. This alone is incredibly significant
in choosing the MegaSampler over a
According to Weber Scientific sales
manager, Asif Rahman, the MegaSampler
will enhance a plant’s food safety program. It will do a much better job than
the swab in many, if not most, sampling
sites. Perhaps it is time to begin using a
device expressly developed and tuned for
the food and beverage industries as contrasted with a swab limited by its original
design for clinical samples.
MegaSampler is manufactured and
distributed by Weber Scientific.