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update to Detection Methods
Tempère et al. (2019) developed what they suggest is a better way to test for mousy off-flavor in wine via oral sensory, specifically as a way to enable panelists who are not as sensitive to THP to detect it during sensory testing. They compared the alkaline strips method to a method where the wine's pH is increased by adding sodium bicarbonate to a pH of 5 and a pH of 7. This mild base is contained in human saliva. At a pH of 5, sensory panelists were more easily able to detect APY and to correctly order the intensity of APY in wine than when they used alkaline strips. For example, the range of detection level for all panelists went from a range of 15 - 300 µg/L to a range of 0.3 - 30 µg/L. At a pH of 7, panelists were not as easily able to detect the aroma of APY. Keep in mind that this test does not reflect the real world tasting of wine since the pH would never be raised during normal consumption, but it could be used by a sensory program as a way to more reliably detect smaller amounts of APY in wine <ref name="Tempère_2019">[https://oeno-one.eu/article/view/2350 Comparison between standardized sensory methods used to evaluate the mousy off-flavor in red wine. Tempère, S., Chatelet, B., de Revel, G., Dufoir, M., Denat, M., Ramonet, P.-Y., Marchand, S., Sadoudi, M., Richard, N., Lucas, P., Miot-Sertier, C., Claisse, O., Riquier, L., Perello, M.-C., & Ballestra, P. 2019. DOI: https://doi.org/10.20870/oeno-one.2019.53.2.2350.]</ref>.
Other techniques for detected THP in food have been developed, which might be applicable to wine or beer. For example, Grimm et al. (2001) developed a technique for detecting 2-acetyl pyrroline (APY or 2AP) in rice. The rice samples had to be heated to 80-85°C in order to extract the volatile APY, and then APY levels in the headspace of the rice container could be detected using solid phase microextraction (SPME) with fibers that operate at the higher temperatures <ref>[https://www.ncbi.nlm.nih.gov/pubmed/11170584 Screening for 2-acetyl-1-pyrroline in the headspace of rice using SPME/GC-MS. Grimm CC, Bergman C, Delgado JT, Bryant R. 2001.]</ref>. It isn't known if such methods would also work for measuring THP compounds in beer or wine, but they could provide a potential option for beer and wine researchers. Cider makers have used a baking soda in water solution to help detect THP. Dissolve a small amount of baking soda in water, swish the solution in your mouth for a few seconds, and then spit it out. While the pH of the saliva in your mouth is raised from the baking soda solution, taste the beer/wine/cider to more easily detect THP <ref>[https://groups.google.com/g/cider-workshop/c/a9JcCERQTYk?pli=1 "testing for mouse". Testing for Mouse. Retrieved 04/06/2021.]</ref>. The effectiveness of these methods in beer has not been reported to our knowledge (please report any research or anecdotes in the [https://www.facebook.com/groups/MilkTheFunk/ MTF Facebook group]).
===University of Southern Maine Methods===