Strain of Highly Pure, Unpolluted Houseflies Kept for 50 Years.
In order to establish a world's leading public health and disease prevention system, the United States devoted resources to investigate disease vectors in 1950. In order to help Taiwan understand these disease vectors, the US military introduced highly pure, unpolluted laboratory houseflies from the United Kingdom to be research subjects in the US military healthcare system. These living organisms were well preserved in an environment with constant temperature and humidity. The flies ate specific pure food and lived in a strictly monitored room at a fixed temperature in order to ensure that the strain would not be affected by environmental conditions and accordingly experience genetic mutation or resistance.
Houseflies and Pesticide Testing.
Since pesticide abuse and residue was an issue gradually gaining prominence in Taiwan, the Taiwan Agricultural Research Institute screened all available living strains in Taiwan when performing pesticide detection experiments. After a series of tests, researchers found that houseflies of the specific strain from the United Kingdom were not polluted by external substances because they were preserved in a closed room and they naturally maintained a high sensitivity toward toxins in pesticide. In addition, neurological enzymes extracted from the houseflies appeared to be very sensitive in biological tests. Researchers could quickly detect minimal pesticide residue, highly meeting the needs of biological test reagents to be developed. As such, the researchers investigated deeper the houseflies from the United Kingdom.
Technical Threshold in Breeding Houseflies.
It is not easy to raise enervated British houseflies because living things tend to gradually adapt themselves to an inferior environment and develop resistances. Once the sensitive British houseflies come into contact with the external environment and developed genetic mutation, even if they survive, they lose the sensitivity they originally had toward toxic agents. As such, these British houseflies have to live in air-conditioned rooms, drink milk made of high-end formula, and eat imported yeast throughout their lives. They lead lives even more comfortable than that of a human. Unlike wild flies that already developed resistance to pesticide, these highly sensitive houseflies can only live indoors. If the room they live in is disinfected or experiences even slightly drastic environmental changes, they will die. This is also why enzyme detection agents made from these houseflies are sufficiently sensitive.
Besides preserving the strain of houseflies, it is difficult to produce and extract enzymes from houseflies because all houseflies have to be the same size. Since removing the heads of houseflies requires the separation of the head from the body using a sifter, if houseflies are too small, their heads may not be separated and mixed with their bodies. Therefore, the mixture will have to be discarded. In order to handle this challenge, the research team tried many different milk and yeast options and found a formula that could help houseflies grow into the same size.
"Testing before Eating" to Safeguard Health.
Nowadays, housefly enzyme and rapid bioassay of pesticide residuals are available at individual agricultural products testing stations to safeguard food safety for consumers. The US military from 50 years ago never would have expected that the hard work of farmers would pay off, ensuring that consumers receive safe agricultural products while high- risk fruits vegetables are quickly taken off the shelves.