Spanish vending specialist Jofemar manufactures the machines, 300 of which are due to be installed around Shanghai, with others either in place or on order for businesses and transport hubs in Poland, Australia and the US.
The Simple Steps Gourmet format combines a tray usually polypropylene with skin film, which adheres to the tray once inside the vacuum chamber, explained Dr Sidi Chouikhi, technical director for global ready meals at Sealed Air Cryovac Food Solutions.
Steam-assisted cooking in Sealed Air's High Pressure Sous-Vide system extends shelf-life to up to eight weeks (with refrigeration) while halving pasteurisation time in comparison with tray-and-lid combinations, said Chouikhi. High pressure means there is no water evaporation in the process and no cook-out for proteins, while vacuum improves heat transfer.
"The skin balloons up during heating, to create a large headspace," said Chouikhi. "This retains the vapour and at a certain size will start to self-vent." Importantly, there is no need for the vent to be created before heating can begin.
Explaining the slowness of western European countries to adopt these systems, he said: "Many people are not even aware of the existence of vending systems where everything, including heating, takes place inside the machine."
Each Jofemar unit can accommodate up to 100 packs, which will heat up in 4075 seconds, depending on the contents.