The mineral composition of fruits is closely correlated to the level of rots found after medium or long-term Controlled Atmosphere (CA) storage.
Increased levels of nitrogen and potassium are associated with higher levels of rots while increased calcium levels in the fruit tend to reduce rot incidence. The importance of adequate concentrations of calcium and phosphorous in apple fruit has been well established through research during the past 30 years and fruit mineral thresholds have been defined for ensuring a high probability of freedom from both fungal wastage and physiological disorders.
Samples of fruit for mineral analysis should be taken from orchards which may be stored, two to three weeks prior to harvest. The suitability of fruit for storage is based on the results of the mineral analysis. Details of sampling and fruit internal standards can be found in Section 3 – Storage, packing and marketing.
The suitability of the fruit from an orchard for storage is the most important aspect of rot risk assessment. If the fruit is not suitable for storage then it will be scheduled for early marketing and storage rot risk is in most cases irrelevant.