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Ethylene absorbers work by removing the ripening gas that fruits and vegetables give off. In controlled trials, dropping ethylene from a normal refrigerator level of about 100 ppb to near zero extended broccoli from 14 to 35 days and iceberg lettuce from 12 to 35 days at 0–5 °C (Wills et al., 1999).

A kitchen is not a controlled trial. It is opened constantly, it is humid, and humidity cuts a permanganate absorber to roughly 15% of its dry-air performance, with removal falling to about 10% of incoming ethylene after two weeks (Wills & Warton, 2004). Home crisper ethylene also varies about eightyfold between fridges, from 0.02 to 1.58 ppm (UC Davis Postharvest).

So the numbers here are deliberately smaller than the laboratory figures: one to four days, for produce in a closed drawer or bag with a fresh sachet. Sensitivity and production classes come from the UC Davis commodity tables and baseline shelf life from University of Maine Extension Bulletin #4135.

Where we publish a zero. Twenty-five items on this list get no day claim at all. Grapes, cherries, peaches, plums and nectarines showed no measurable response to continuous ethylene across three to eight weeks of cold storage (Wageningen University & Research). Onions and garlic are dry pantry crops, and ethylene actually suppresses onion sprouting — it is sold commercially as a sprout inhibitor (Forney et al., HortScience). Potatoes are genuinely contested in the literature (Rylski, Rappaport & Pratt versus AHDB). And the one head-to-head trial of an absorber in mushroom packaging found no difference in shelf life (Gıda / DergiPark). Apples are the largest ethylene source in most fridges and out-gas any sachet, so the useful advice there is to store them apart, not to buy an absorber for them.