**3. Challenges affecting hot water treatment technology**

Though various protocols have been developed in Africa and elsewhere, adoption by the private sector has been slow and absent in many parts of Africa. Protocols have remained on shelves unused. Most of these protocols have been developed used using water baths using very small sample sizes which can hardly be extrapolated to commercial scales. In some cases, the studies are silent on the equipment used and how heating, water circulation, and temperature regulation were achieved yet these are vital components of any HWT system. The stage of maturity of fruits is another factor that largely affects the quality of treated fruits. Most often, immature fruits are harvested by growers in a bid to ensure that they stay longer on the shelf. Maturity indices are also lacking and growers rely on visual characteristics which are not always accurate. The aspect of maturity is bound to be the sticking point because avocadoes and mangoes are bulky and are likely to be exported by sea to reduce transport costs, thus fruits are bound to be harvested earlier before reaching full physiological maturity to withstand the long voyage to Europe, America, India or China.

Resources are a limiting factor in adopting HWT in Africa with various small to medium scale enterprises unable to gather adequate startup capital. However, in our experience, we have noticed that some private sector partners have misplaced expectations, and require out-of-this-world automated facilities yet the HWT itself is simple and affordable. We opine that it is far much cheaper and easier to run and maintain than a VHT facility of similar size and capacity. Hot water treatment protocols for disinfecting fruits and vegetables usually prescribe a longer treatment duration which may be put off to potential users. The insistence of probit 9 as the required quarantine efficacy level frequently overestimates treatment times. This can be evaded by adopting other statistical analyses which equally show how effective a treatment is.

The emergence of less stringent markets in the Middle East has also provided local fruit growers and exporters with alternative markets where they send

*Advances in Postharvest Disinfestation of Fruits and Vegetables Using Hot Water Treatment… DOI: http://dx.doi.org/10.5772/intechopen.100351*

their products with less hustle. Thus investing in HWT equipment is seen as an expensive venture.

The lack of holistic protocols validated at a large scale has also been another impediment. There is a need to validate the most promising protocols and seek buyin from major industry players if HWT is to be fully adopted at a commercial scale. Poor circulation of water and regulation of temperature also impact the quality of fruit. Hot water treatment requires a sizeable investment into good probes, data loggers, and automated controls. Too much fluctuation of temperature during treatment can be detrimental to the final product. Combination treatments are poorly developed or are simply expensive to implement. In cases where HWT cannot be a stand-alone treatment due to the susceptibility of the commodity to heat, combination treatments may then be used to circumvent the challenge. If there is a mismatch in heat tolerance between the commodity and pest, for example in instances where the pest is tolerant to higher levels of heat which cannot be tolerated by the fruit or vegetable, then HWT will not be feasible [85]. Thus the above suggestion may work.
