8.3 The increasing role of non-chemical controls

Established practice, together with more recent research and development [1], has shown that infestations of stored produce can be managed by:

General sanitation: as with most pest control, basic measures must be taken to prevent the carry-over of infestations by cleaning and clearing up debris that can harbour pests.

Maintaining a low moisture content: In most stored crops, if moisture content is reduced to below 8%, all metabolic activity of any organisms present practically ceases. 

Drying is therefore a standard treatment before storage, but may require external energy and air movement to evaporate the moisture and remove the resultant water vapour. 

The energy may be derived from burning fossil fuel or wood (but care must be taken to ensure that the cocoa beans do not come into contact with smoke, since this will result in loss of quality and food safety issues), or from solar energy, as in sun-drying. Drying processes are well documented and results can be predicted reliably.

Other methods: such as the use of modified atmospheres (MA), where oxygen availability is reduced and temperature is well controlled (insect activity rises with increasing temperatures up to 42°C). 

These methods were rarely used in cocoa until steps were taken to withdraw the important fumigant methyl bromide (restricted under the International Montreal Protocol Agreement because of concerns about ozone depletion). 

Treatments involving MAs such as carbon dioxide have been investigated widely and are now seen as acceptable and viable alternative treatments.