2.4.1. Field and Packing Shed Horticultural Postharvest Losses

Quantification of loss was based on weight or volume, consistent with direct measurement methods of the *FLW Accounting and Reporting Standard* [40]. Field losses were determined by counting the number of individual pieces of fruit of commercial maturity (one-quarter to full-colour fruit) that remained in-field immediately following a completed harvesting cycle, based on a sub-sample of 608.18 kg, within a transect of 1311.80 m2. Field losses were then calculated relative to a total harvested area of 8.5 and 12.14 ha respectively for SC1 and SC2. Field loss was defined as mature fruit left on the vine or product on the ground left by the harvest aid and/or bucket pickers, or discarded from the harvest aid where preliminary discarding of product was performed. The primary destination of all field loss was via 'land application'. 'Land application' is the term used to describe the destination whereby losses are discarded through spreading, spraying, injecting, or incorporating organic material onto or below the surface of the land to enhance soil quality [40].

During the harvest of SC1, a sub-sample of 100 fruits was taken to determine the mean weight of a single tomato at the field and packing shed stages of the supply chain. During the harvest of SC2, three random sub-samples of discarded field and shed product were utilised to determine the causal factors of out-grading. Product that left the supply chain was deemed unsalable based on product specification (i.e., physical blemishes/abrasions, size and shape), colour and maturity, or physical damage (punctures or pathogenic deterioration).

Postharvest loss in the on-farm packaging shed was calculated based on the volume of product removed during sorting and grading, proportional to total volume of product initially arriving at the shed. Packing shed volumes were based on a count of harvest bins with a mean net weight of 330 kg, entering and leaving the packing shed during a complete harvesting cycle. Saleable product was packaged in 10-kg cardboard cartons, and pre-cooled prior to transportation to market within 24 h. The destinations of packing shed losses were partially quantified; they were used for 'land application' and 'animal feed'. 'Animal feed' refers to destination of loss by diverting material from the food supply chain (directly or after processing) to animals [40]. Truck transport for the discarded product was empty at the commencement and cessation of the sampling period. To further validate loss at this stage, packing shed losses were recorded for a further two days consecutive to the SC2 trial period using the same method.

As SC2 represented a late seasonal harvest and was immediately followed by an abrupt cessation of seasonal harvesting due to depreciation of the market, we were also able to determine pre-harvest loss and destination of loss, independent of the SC1 and SC2 postharvest loss trials. Pre-harvest loss included unharvested product from the commercial harvesting cycle, being mature residual product remaining in-field on or off the vine, at the cessation of the commercial harvesting season. On completion of seasonal harvesting a field of 3.64 ha was defoliated in preparation for the next seasons planting. An assessment of pre-harvest loss was undertaken to determine percentage loss relative to the volume of the entire seasonal harvest for the field. Twenty-six trellises were randomly selected within the field of 8400 trellises. The number of individual fruits remaining on each vine was counted and recorded for each trellis and later extrapolated across the field's entire seasonal harvest based on carton volume leaving the farm.
