4 Pest control
Pest control is targeted at reducing the losses associated with pest feeding and spoilage or micro-organism invasion and contamination. Rodent control is a continuing problem but sanitation and clean practices, aided by well-built storage facilities and the strategic use of baits, help keep the problem in control. Storage insects can also bring significant damage to the stored crop. Good quality storage facilities that can be cleaned and fumigated before the harvest will help pest management. There is on-going strategic management fumigation needed in storage facilities. As noted previously, cleaning and packaging after drying can assist in pest control. Micro-organism spoilage often starts in the field, or with contaminated equipment and is carried from the field to the store. High humidity is the crucial factor encouraging fungal infection. The drying of the crop and moisture control in the storage facility is of primary importance in controlling fungal invasion. The use of preventative measures such as sterilizing equipment or disinfecting with antiseptic solutions all aid in reducing fungal outbreaks.
Pests can be general to stored produce or specific to a crop [13] . Common stored product pests such as the drug store beetle or the tobacco borer beetle attack stored ginger. A range of storage pests and particularly the nutmeg weevil eats stored nutmeg and mace. Spice beetle and cigarette beetle attack chillis during storage. Rats also have a great liking for chillis and the storage method should protect against this pest. Chilli and paprika spice is vulnerable to contamination from mould toxins particularly the aflatoxins. Vanilla is prone to mite attack that encourages spoilage. Fumigation can be needed with severe invasion. Harvesting management and fermentation practice can be critical to keeping mites under control.
4.2 Relative status of major pest species
Spice and herb crops, because of their essential oil content, have an enhanced ability to keep pest invasion to a minimum provided the crop has been dried to correct specification and stored in temperature and humidity controlled conditions. A major problem can be rodents or fungal invasion but these are secondary causes due to inferior facilities and less than ideal management. Produce which has field insect contamination can be extracted for essential oil production and provided these oils are stored in clean sealed drums in a cool environment, there is little likelihood of pest spoilage.
The usual principles of pest and disease control apply. Pest and disease pressure should be minimised before harvest. Grading restricts the passage of pests and diseases into the stored product. Many micro-organisms are effectively controlled by the low moisture content of well-dried herbs and spices making further chemical treatment unnecessary, as long as strict attention is paid to the maintenance of a dry product through effective packaging. For example, in chillis, using an integrated strategy best controls aflatoxins . Initially disease in the field needs to be controlled by preventing insect damage to the fruit. At harvest, diseased and damaged fruit should be removed to prevent the source of moulds. Fruit should be processed immediately after harvest or stored under refrigeration. During processing, conditions need to be constantly controlled to ensure the moisture content is always below 11% and moulds cannot grow.
Two physical processing methods are effective for the control of pests in spices: the use of microwaves and ionising radiation. Microwaves penetrate the food and are converted to heat in areas of high water content. Ionisation treatments consist of exposing the dried spices to gamma radiation or X-rays. The doses used and permitted on food never render the products radioactive and ionisation does not leave any residues. For example , there are several methods available to sterilize dried pepper including hot air or steam, gamma irradiation, chemical or microwave use. Gamma irradiation is considered to be a superior method for sterilization and insect disinfestations due to its ability to treat pepper that has been pre-packed. As irradiation is a cold process the loss of volatile or flavour components is overcome, and this process does not leave harmful residues.
As noted previously (section 1.5), pest contamination in spices will always be identified by the importing country and can lead to consignment rejection or reduced prices because of extra processing. The FDA Technical Bulletin Number 5 on macro-analytical methods for spices, condiments, flavours, and crude drugs details the procedures to quantify the contamination (see http://www.cfsan.fda.gov/~dms/mpm-5.html).
