Abstract: The invention is a method of measuring oxygen concentration in a package having an oxygen sensitive product disposed therein. The method includes exposing a luminescent compound that is disposed in an interior of the package to light having a wavelength that is absorbed by the luminescent compound so that the luminescent compound is promoted into an excited state. When the exposure of the light is terminated, the excited luminescent compound emits light that is detectable by a detector positioned outside of the package. The intensity of the emitted light is inversely proportional to the oxygen concentration and is used in conjunction with mathematical function that describes the luminescent intensity of the luminescent compound as a function of oxygen concentration and temperature to calculate the oxygen concentration. The method may be used to verify and track the oxygen concentration of a package as it moves through a distribution system.

Abstract: The invention is a modified atmosphere package comprising about 0.1 to 5 vol. % carbon monoxide and that includes a time-temperature indicator that is disposed in a temperature monitoring relationship with the package and that is configured to indicate whether a perishable product disposed in the package has been exposed to a time-temperature exposure that may have caused spoilage of the product. The time-temperature indicator may be used to alert a person that a red meat product disposed in the package has potentially spoiled even though the meat product may have a fresh “bloomed” appearance. As a result, the possibility of a consumer purchasing a spoiled product may be reduced. The invention is also directed to a method of using the time-temperature indicator to indicate the likelihood of spoilage in the packaged product. In one embodiment, the time-temperature indicator changes visual appearance based on a combination of predetermined times and temperatures.