Rates of carbon dioxide production, in air and in 3 yo 0,, over a range of temperatures, were measured for over thirty commodities, and rates of evaporation, under known water vapour pressure deficit, measured for most of them. Optimum storage conditions in air for each commodity were determined. Storage life under these optimum conditions, and under the nearest practical approximation to them, was estimated. I n most cases the optimum temperature is o "C, examples of exceptions being runner beans, cucumbers, potatoes, green peppers and tomatoes. The humidity should usually be high,

An experimental retail packaging system was used to compare the atmospheric composition and relative humidity which developed within packs sealed with a range of plastic films with different permeability properties, and to study the effects of these conditions on the rate of ripening (as indicated by colour change) and sensory quality of tomatoes. In packs sealed with several polyvinylchloride (PVC) films or with K-resin (a butadiene-styrene copolymer), an atmosphere containing 3-9% CO,+3-9% 0, developed within circa 3-4 days at 10 or 12.5"C. Ripening of part ripe fruit was retarded, but continued normally after the packs were perforated, with no obvious adverse effects on the smell, flavour or texture of the fruit. In packs sealed with less permeable films (e.g. cellulose acetate), the internal atmosphere equilibrated to 10-18% CO,+ < 2% 02, resulting in complete inhibition of ripening, a high incidence of rotting and tainting of the fruit. Very high (98% or above) relative humidity within sealed packs also encouraged fungal spoilage. The possible commercial applications and benefits of this type of modified atmosphere (MA) packaging are discussed.

No abstract

In a survey of nine carrot crops stored during four seasons 1978 -82, the major causes of wastage were spreading soft rots caused by Botrytis cinerea and Rhizoctonia carotae; rots caused by Sclerotinia sclerotiorum, Mycocentrospora acerina and StemphyIium radicinum were only of secondary importance. Storage weight losses were lower and roots remained turgid for up to 40 wk in an ice-bankcooled store at 0.5 "C, 97 -98% r.h., whereas carrots in conventionally-cooled stores at 2 -2.5 "C, 90 -95% r.h. became flaccid after a few months. In some crops, losses due to fungal spoilage were also lower in the ice-bank store. In two seasons' losses, mostly due to B. cinerea, were similar in hand-and machineharvested roots ; pre-storage washing of carrots grown on mineral soils increased the incidence of Botrylis rots, and reduced rotting by R. carotae, but had no effect on spoilage of roots from peat soils. Post-harvest fungicide treatment with benomyl or iprodione (0.5 g/litre a.i.) effectively reduced rotting by B. cinerea and S. sclerotiorum, but not by R. carotae. The recoveries of sound carrots after 23 -29 wk storage were consistently highest (mostly > 80%) from fungicidedipped roots stored under ice-bank conditions, but recoveries from all treatments were lower and more erratic after 35 -40 wk because of increased fungal spoilage.The practical applications of long-term ice-bank storage of UK-grown carrots are discussed. 0 1988 Association of Applied Biologists 504