One machine that does this is a new cold-catalyst ethylene scrubber, which is being trialled this season. It should be commercially available next year. This French model, which requires less heat than is produced by running a 60W lightbulb, is already being used quite extensively in kiwi-fruit stores to extend the fruit's storage life, said Ken Hatch. He runs UKCA, specialising in controlled-atmosphere storage systems.
"We're trying to get the size of the new machine right so that it removes the correct amount of ethylene from the stores," Hatch said.
"It will be less expensive than the hot-catalyst scrubber, which costs about £15,000 for four stores. We expect the cold-catalyst machine to pay for itself in five years."
Hatch claimed that the new scrubber can do a better job than SmartFresh, whose effect generally lasts only until March and costs £1,200 to £1,500 per store.
So far, however, he is not certain whether the scrubber is as good as SmartFresh for controlling bitter pit, although it reduces the amount of rotting that tends to be greater with the widely used five per cent oxygen/one per cent carbon dioxide Bramley storage regime.
The hot catalyst scrubber has proved very effective for Gala, he said. It has the advantage over SmartFresh of greater flexibility in that the machine can be turned off two to three weeks before the store is opened for marketing. This allows the fruit to develop its full flavour without loss of firmness.
The catalyst for the hot scrubber is platinum, while titanium oxide is used for the cold scrubber model.