Modified Atmosphere Packaging:
Modified atmosphere packaging (MAP) broadly defined any type of packaging system that attempted to modify the atmosphere inside the package to extend the life and freshness of the produce. MAP was the result of an imperfect science that had risen in popularity since its success in preserving fresh-cut vegetables and salads in the 1990s. Iterations of MAP for fresh produce had focused on filling a container with a carbon-dioxide-rich gas mixture or using a bag that retained the produce's naturally produced carbon dioxide. As produce respired and removed oxygen from the air, the atmosphere reached an equilibrium that contained low levels of oxygen and high levels of carbon dioxide. At low oxygen levels, respiration and therefore aging took place at a much slower rate than at high oxygen levels. Maintaining the correct balance in the atmosphere was important because if oxygen levels dropped too low, the produce could not breathe and would die.
While all MAP options aimed to make their advantage the extended life and freshness of the product, each struggled with a multitude of issues. In the case of a package using a sealed injected atmosphere, the atmosphere could not adjust as the product respired, the produce could not be cooled by refrigeration because the package had no air holes, and the packing process required a special vacuum or gas injection process. In the case of the bag-in-a-box method, the bag constricted natural respiration and lacked sufficient circulation to be cooled by refrigeration, and the box had to be sealed by hand to avoid puncture.
Other issues-such as those linked to the packager's inability to manipulate temperature after sealing, standardization to typical produce shipping requirements, durability and strength in shipping, and scalability across different types of produce-left MAP commercially unviable without significant improvements.