Detecting ammonia injury on stone fruit

Abstract

The minimum ammonia concentration that injures stone fruit ranges from 0.04 to 0.3%, depending on the fruit quality and time of exposure to the gas 1–3. Ammonia damage may be expected if there has been an escape of the gas from refrigeration machinery. When ammonia odour is not noticed, visual symptoms of the disorder are relied upon to identify the cause of the damage. The symptoms of ammonia damage, especially several days after exposure, may be similar to those of other injurious materials found in the postharvest environment, such as excessive exposure to fumigants used to control insect infestations or to detergents used to wash fruit in the packing house. We investigated two simple qualitative chemical tests to detect ammonia residues.