For as long as humans have eaten fish, we’ve identified rot or spoilage by looking for a handful of physical signs. Researchers at the American Chemical Society believe their new “microneedle based freshness sensors” device could make that process much more efficient. Several microneedle sensors attached to the fish immediately begin emitting an enzyme that disturbs molecules associated with rot. Overall, the researchers observed a, “progressive increase in HX levels over time,” with concentrations rising steadily throughout the entire test period. For now, it is also limited primarily to measuring fish, because the HX spoilage thresholds at the core of its detection method can vary significantly between animal species.