Establishment of a Freshness-Evaluating Standard for Chilled Yellow Chicken Meat

There is still no uniform criterion to evaluate the freshness of chilled yellow chicken meat in China. Here, we combined traditional methods, which were sensory evaluation, adenosine triphosphate (ATP) and inosine monophosphate (IMP) contents with a novel technology, electronic nose analysis, to determine the freshness of chilled yellow chicken meat. The contents of ATP and IMP in meat were detected by portable ATP detector and high-performance liquid chromatography (HPLC), respectively. In the first 3 days post-slaughter (dps), sensory evaluation scores were greater than or equal to 4, which indicate freshness. Chicken meat was deteriorated at 6 dps. As chemical indicators, IMP content was higher than ATP content, and both gradually decreased, with fluctuations. The most significant differences appeared at 3–5 days, similar to sensory evaluation results. All indicators above were different between male and female, the same rule was available between breast and thigh. We were able to distinguish the storage time, different body regions, and odors of samples using electronic nose. In the first 3 dps, few changes were found in the G ₀/G eigenvalues for each sensor, which all reached a minimum at 4 dps. In conclusion, the traditional methods and novel technology are fit for evaluating freshness, and the electronic nose is recommended to evaluate the freshness of chicken meat owing to greater speed, ease, and accuracy. To summarize the results of the three tests, we rank meat at or before 3 dps stored at 4 °C as “fresh grade,” from 3 to 5 dps as “second fresh grade,” and 6 dps and later as “non-fresh grade.”