Microbiological contamination of the spice largely results from the long ‘fermentation’ process and the length of time required for sun-drying during which the berries are exposed to the elements. Contamination can be minimized by preventing the berries from coming into contact with the soil during harvest and handling and by drying on suitable raised racks. The problems of infection by micro-organisms and mould formation are greatly reduced if the berries are dried by artificial means. The temperature of drying must be carefully controlled, however, and it should not exceed 75 C since at higher temperatures loss of volatile oil by evaporation can ensue. Artificial drying of the berries by exposure to smoke from a wood fire can detract from the aroma of the spice.

The dried berries should be stored under as hygenic conditions as possible in a cool, dry atmosphere to prevent quality deterioration. The susceptibility to further infection by micro-organisms and development of mould are reduced by maintaining the moisture content of the spice below 12 per cent.

The principal alternative sources of pimento are Mexico, Guatemala and Honduras, where the bulk of the crop is harvested from wild trees. Central American pimento is generally regarded as greatly inferior to Jamaican pimento in appearance, aroma and flavour strength and quality, and in volatile-oil content. The Central American spice normally has a higher proportion of larger-sized berries and the colour is more variable, ranging from pale brown to black. The volatile-oil content is usually below 3 per cent and is frequently less than 2 per cent. This material is employed mainly for grinding and blending purposes.

The berries are turned several times by raking each day so as to obtain an even browning. During the night or during rain, the berries are either taken indoors or are swept up into heaps and covered with a tarpaulin. Sun-drying takes up to five days during dry weather or up to ten days during unsettled weather. On completion of drying, the berries attain a medium to dark brown coloration and have a moisture content of about 12 per cent. A yield of 52-62 kg of the spice is obtained from 100 kg of green berries.

However, if this suggestion were adopted in commercial practice, mould development usually would begin to appear after three or four days, and in addition, the final dried berries might be extremely brittle and easily broken. During sun-drying of the berries, whether ‘fermented’ or not, care must be taken to ensure a uniform colour development by regular turning and to reduce the moisture content as rapidly as possible to a safe level (12 per cent) to avoid mould formation.

It was found that, in a pilot-scale version of the drier, 270 kg of fresh berries heated by air at 70-75 C and with a linear flow rate of 25 cm per second, dried down to a moisture content of under 12 per cent in about 8 hours, without significant loss of the volatile oil and to a satisfactory colour. This method holds considerable promise in reducing bottlenecks encountered in traditional sun-drying during wet weather and a larger-scale artificial drier is being investigated.

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