Wednesday, October 5, 2011


Fight between man and insects for accessing available food on the earth is as old as the planet itself and many insecticides and pesticides have been evolved as a part of the armory against these vectors. There are thousands of insects that roam allover but food industry is bothered by a few of them which infest foods during production, handling, storage and processing. Though lately use of chemical insecticides is not favored by consumers and health activists, it is difficult to envision a world without the use of one or the other chemicals to prevent spoilage and irreparable loss of many types of foods. It is variably estimated that a significant proportion of food is lost during its travel from the farm to the consumer table and such losses could be as high as 30% in many cases. The million dollar question that faces the humanity is whether the world can afford to loose this much food for the spoilage vectors while a substantial segment of the population go hungry being denied access to limited food resources.  

Organic food movement which started in a small way is becoming a force to reckon with because of the apprehension weighing heavily in the minds of people regarding the uncertainties associated with many chemicals used at different stages while growing and processing of food crops. Many of such chemicals have been implicated in diverse health disorders including different types of cancer. There are many chemicals, used extensively earlier, now being discontinued after reliable scientific findings raised serious doubts about their safety for use in foods or processing facilities because the levels of residues left over can expose the consumer to unpredictable adverse health consequences. One major reason for the emerging clarity on safety is the advancement in residue analysis methods and more reliable research tools capable of monitoring residues in parts per billion concentration. For example Aflatoxin levels in peanuts and derived products which pose high risks of damage to liver can now be estimated in ultra low level concentrations and safety standards for limits for this mold derived toxin are continuously going down during the last few years. Same is true in many cases with buyers increasingly demanding zero level contaminants.

Recent proposal in the US regarding banning of a widely used pesticide Sulfuryl Fluoride (SF) is raising shackles in the food industry because of the repercussions such an action can cause to the present infestation control protocols. This chemical was in wide use in non food area, especially in the treatment of wood products against termite attack and it became an option for the food industry after the ban of Methyl Bromide (MB) in the year 2005 because of its role in depleting ozone layer in the atmosphere and consequent global warming process. It may be recalled that MB was a very effective fumigant because of its quick action and SF became the next option as it is equally effective against many stored products insects. The basis for present rethinking is the apprehension about the likely deleterious effect of fluoride on dental health causing fluorosis leading to tooth pitting and destruction of the enamel cover of the teeth. Conclusive evidence is still lacking whether the level of residues in treated products can cause any such harm as being claimed by the antagonists of SF. 

A point which has been overlooked is that only a few food products like cereal grains, dried fruits, coffee beans, cocoa beans and tree nuts are exposed to SH fumigation and there is no clear data as to how much is left behind as a residue in these treated products. SH fumigation usually for about 18 hours at controlled levels, is always followed by aeration for at least 6 hours and it may be too presumptuous to expect large scale absorption or chemical interaction of SH with the foods treated. Is it not odd that on one side WHO is promoting Fluoridation of water and inclusion of Fluorides in tooth pastes for the protection of teeth while SH use in small quantities for protecting foods is opposed by some! It is well known that exposure to fluorides through residues remaining in treated food products constitutes less than 3% of the total exposure of the population from other sources like tooth pastes, mouth wash products and fluoridated water. Yet the US government wants to single out SH for a ban in 3 years' time! The logic used for justifying the ban is that certain categories of population like children under the age of seven and those living in areas where water contains high levels of fluorides are more vulnerable to any additional exposure to fluorides through foods. 

It is not that there are no alternatives available to the industry beyond Sulfuryl Fluoride because chemicals like Phosphene, Ethyl Formate,  Ethylene Oxide etc are still "usable" chemicals against many species but most of them are not favored for one or the other reason. Alternatives being suggested by those proposing to ban this chemical include use of phosphene gas and heat which in theory can achieve disinfestation satisfactorily. But from a practical view Phosphene takes any where from 3-15 days of contact application to have kill all insects besides it being a fire hazard. Also true is that Phosphene can seriously damage monitoring instruments due to its highly corrosive nature. As for heat bringing the environmental temperature to 69C can kill most insects but practically it is not possible to put into practice a reliable heating system that can ensure uniform temperature in large establishments. One has to also keep in mind the adverse impact such high temperature may have on the equipment and other facilities in food processing and storage places. To come up with an equally effective pesticide like SF, it may take years of research and safety assessment and can the world wait for so long while food losses may mount to uncontrollable levels?. World should unite to discourage the US from going ahead with the ban and agencies like the WHO must advise its member countries to desist from following the unjustified course of action of the US.   


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