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Biosensor for food freshness is needed
by Mitch Sanders
Mass High Tech: The Journal of New England Technology - May 22, 2006
There should be 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. Improper holding and storage temperatures are the leading risk factors associated with food-borne illness and spoilage. If the integrity of a hot dog package is damaged during shipping or in stocking the grocery shelf, then the product can spoil earlier than the predetermined date. Improper handling can also lead to contamination. 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 10 million or more colony-forming units of bacteria. But modern science can provide a test to determine whether poultry or meat has begun to spoil before the onslaught of disgusting and offensive odors.
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.
To "digest" cell tissue, bacteria secrete protease, an enzyme that converts 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 small chains of proteins called peptides 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. 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.
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 food liners (diapers) on which chicken, pork or meat rest in packages. The biosensor would offer consumers an easy-to-comprehend visual signal for freshness.
What's the holdup?
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.
by Mitch Sanders
Mass High Tech: The Journal of New England Technology - May 22, 2006
There should be 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. Improper holding and storage temperatures are the leading risk factors associated with food-borne illness and spoilage. If the integrity of a hot dog package is damaged during shipping or in stocking the grocery shelf, then the product can spoil earlier than the predetermined date. Improper handling can also lead to contamination. 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 10 million or more colony-forming units of bacteria. But modern science can provide a test to determine whether poultry or meat has begun to spoil before the onslaught of disgusting and offensive odors.
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.
To "digest" cell tissue, bacteria secrete protease, an enzyme that converts 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 small chains of proteins called peptides 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. 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.
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 food liners (diapers) on which chicken, pork or meat rest in packages. The biosensor would offer consumers an easy-to-comprehend visual signal for freshness.
What's the holdup?
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.