 |
 |
 |
 |
 |
 |
A Biosensor for Food Freshness
DATELINE: — January 9, 2006 — ECI Biotech ChickenSense™ Biosensors will provide a scientific basis for determining the freshness of poultry or meat
How often do consumers go to the grocery store and buy
a chicken breast – only to bring it home and find that it
already smells?
The rancid odor associated with spoilage is caused by
the presence of thousands – even millions - of bacteria. A
simple test, however, could detect the existence of
multifold bacteria. Such a test would provide a real
measure of freshness, and possibly even help prevent food
illness.
Meaningless “Sell-by” Dates
Sell-by dates marked on meat and poultry packages are
arbitrary time stamps. Although many grocers and food
producers do microbiological research to determine how long
their product stays fresh under normal conditions, the
sell-by dates are affixed when the meat or chicken gets
packaged at the plant or in the supermarket. If the
integrity of the hotdog package is damaged during shipping,
or in stocking the grocery shelf, then the product can
spoil earlier than the pre-determined date. Improper
handling can also lead to contamination. Hence a mouthwatering
filet mignon steak or plump chicken breast may
look fresh, but the most appealing food product in the
grocery store may not be what a consumer wants to cook and
eat.
The company ECI Biotech recently conducted a spoilage
test of 100 store-bought chickens with premium chicken
breasts fresh from a production plant (kindly provided by
MBA Poultry, Inc.) that demonstrated that consumers can’t
place much trust in sell-by dates. Although the chicken
breasts carried statements on their packages, indicating
that meat was fresh for two weeks from the purchase date,
laboratory tests proved otherwise for a significant
portion. ECI Biotech found that five percent of the
chickens in the sample had between 1,000 and 1 million
bacteria present.
Good meat fresh from a butcher’s shop should have no
more than 100 to 200 bacteria present on it. Air chilled
chicken breasts from MBA Poultry have even less. By the
time a consumer’s nose detects a rotten smell, spoilage
bacteria have already grown from a few early inhabitants on
a chicken breast to a full blown contamination of a million
or more colony forming units of bacteria. But modern
science could provide a test to determine whether poultry
or meat has begun to spoil before the onslaught of
disgusting and offensive odors.
BioSensors
To understand how such a test might be devised, it’s
important to review what science knows about the process of
spoilage. Present almost everywhere, bacteria play a role
in the natural process of decay. These simple organisms too
want to feast on the meat or poultry just like a human
consumer.
To “digest” cell tissue, bacteria secrete protease, an
enzyme that allows it to convert protein into amino acids
for the purpose of metabolism. The foul orders – what makes
kids say yuck – stem from the release of byproducts that
occur when protease initiates the chemical breakdown of
tissue.
Why couldn’t a simple test diagnose the abundance of
protease? Such a test would have to involve interaction
with protease with another substance to enable marking.
Human-manufactured peptides – small chains of proteins
-- provide the basis for such a tag. Since protease will
interact with any protein, it becomes possible to design a
special one for testing purposes. For instance, a peptide
could be constructed containing food dye in its chemical
makeup. When protease then cuts a custom-made peptide, the
breaking of the amino-acid chain could release food dye as
a by-product of the reaction.
As the food dye collects on a surface, it would
provide a simple marker visible to the consumer’s eye,
which would signal a high degree of spoilage bacteria. The
sensor would display a colored dot to indicate a high
degree of bacterial contamination. Think of this diagnostic
tool as a “litmus test” for freshness. ECI has developed a
freshness sensor, Chickensense™ that will be first direct
measure of freshness for the sell by date.
Advancements in applied science make it possible to
manufacture such peptide sensors at an economical cost. For
instance, a peptide-dye conjugate sandwiched between two
membranes could be placed in diapers on which chicken, pork
or meat rest in packages. The biosensor would offer
consumers an easy-to-comprehend visual signal for
freshness. Moreover, these types of bio-sensors could be
laser jet-printed onto poultry or meat diapers.
Consumer Ignorance
Why hasn’t the meat or poultry industry looked into
the adoption of such technology if it’s available for
pennies? No industry wants to take on additional costs
without sufficient consumer demand.
Yet the public is not yet aware that the field of
biotechnology has developed simple, yet low-cost biosensors
for detection of spoilage. Once they become aware that such
diagnostic tools do exist, then consumers may begin
demanding that meat and poultry industry supply “yuck
sensors” on product shipped to supermarkets. After all,
such sensors would ensure that the public spend their food
dollars wisely to obtain the freshest product possible at
the market.
As Americans and other people around the world worry
about the food chain, biosensors offer the ability to allay
consumer concerns about product quality and freshness.
For more information on the development of these low-cost,
diagnostic sensors to detect microbes and other possible
consumer applications, visit ECI Biotech’s website:
http://www.ecibiotech.com.