Fully mature, unripe mangos are ripened in the cannery to optimum canning ripeness. Mangos high in flavour, with more flesh and low in fibre are always recommended for canning.
Sound ripe mangos are soaked in antiseptic and water, brush washed and then conveyed to the preparation tables and hand peeled. “Cheeks” of the peeled mangos are sliced off and longitudinally cut into two or three slices. Side cuts are packed separately. Slices are then conveyed to the filling tables where they are graded for size, colour and maturity and filled into sterile cans. Filled cans are syruped, steam exhausted, sealed, processed in boiling water, cooled, labelled and packaged.
Stones with the left over flesh are steamed and pulped and the pulp thus obtained is packed as such or converted into mango juice or nectar.
A more detailed procedure can be found here.