RESPIRATORY SENSITIZATION TO KONJAC FLOUR IN GUINEA-PIGS

Medical reports linking asthma and occupational exposure to airborne p owder produced during the manufacture of konjac flour have been report ed in the literature. This study was conducted to investigate whether exposure to food grade konjac flour, which is the end product of the m anufacturing process, could produce respiratory hypersensitivity using an animal bioassay developed by Karol et al. (Karol, Y., Ioset, H.H., Riley, E.J., Alarie, Y.C., 1978. Am. Ind. Hyg. Assoc. J. 39, 546-556) . Groups of guinea pigs were randomly assigned to a negative control, a konjac flour exposure group, or a positive control group exposed to trimellitic anhydride (TMA). The study design included five consecutiv e days of inhalation induction exposures followed by three inhalation challenge exposures on days 19, 26 and 40. Positive control guinea pig s were exposed to 98 mg/m(3) TMA during the induction exposures and 57 -67 mg/m(3) TMA during the challenge exposures. The mean (+/- S.D.) ko njac flour concentration during the induction exposures was 111 +/- 8. 3 mg/m(3) and the exposure concentrations of konjac flour during the c hallenge exposures ranged from 50 to 68 mg/m(3). The criteria used to define respiratory tract sensitization (an increase in respiratory rat e of 36% and a change in the respiratory waveform) were met by 25% of the animals at each challenge in the konjac flour group. In addition, a few animals responded with slightly lower increases in respiratory f requency and a change in waveform suggestive of a slight pulmonary hyp ersensitivity response. Guinea pigs that responded during the first ch allenge also responded during subsequent challenges. No changes in res piratory rate or waveform were noted in animals assigned to the negati ve control group when challenged with konjac flour. The results of thi s study indicate that respiratory hypersensitivity to food grade konja c flour can be induced in guinea pigs following repeated inhalation ex posure. Therefore, proper engineering controls or personal protection equipment should be utilized to prevent respiratory sensitization in t hose who may be occupationally exposed to food grade konjac flour. (C) 1997 Elsevier Science Ireland Ltd.