Food poisoning is a scourge.
Yet preventing it is far from foolproof.
But in a new study in Analytical Chemistry, scientists report that they are closing in on a way to use a combination of color-changing paper and electrochemical analysis — on plastic transparency sheets or simple paper — to quickly, cheaply and more accurately detect bacterial contamination of fruits and vegetables in the field before they reach grocery stores, restaurants and household pantries.
Of all the contaminants found in food and water, bacteria cause the most hospitalizations and deaths in the United States.
Nearly half of these incidents are attributed to spinach, cabbage, lettuce and other leafy greens, which are sometimes irrigated with unsafe water containing fecal material.
But traditional lab cultures take up to 48 hours to produce results, and other techniques such as DNA amplification and immunoassays are costly and are prone to false results.
Recently, Charles S. Henry and colleagues developed a paper-based method to detect Salmonella, Listeria and E. coli in food and water samples.
To simulate contaminated food, the researchers exposed clean alfalfa sprouts to E.coli and Enterococcus faecalis bacteria.
They also collected unfiltered water from a nearby lagoon.
For colorimetric detection, the team built a simple light box, which served as a substitute for a laboratory plate reader.