MALEIC HYDRAZIDE JMPR 1977 Explanation Arising out of the list of requirements published in the Report of the 1976 Joint Meeting (FAO/WHO, 1977a) some information on the stability of residues of maleic hydrazide during the cooking of potatoes has been referred to the Meeting. Data, on residues observed in tobacco were also made available. The new information is reviewed below. No new toxicological data have been provided. It was therefore impossible to complete a evaluation or to establish an ADI for humans. RESIDUES IN FOOD AND THEIR EVALUATION RESIDUES RESULTING FROM SUPERVISED TRIALS Tobacco Information was available to the FAO Panel of Experts relating to residues of maleic hydrazide Observed in tobacco and cigarettes in the USA during the years 1961-75 Uniroyal chemical, 1977b). Data concerned flue cured and Burley tobaccos, influence of harvest time, influence of application rate, effect of curing, residues in stored tobacco, and residues in tobacco products. The data from supervised trials collected over 15 years from almost 100 locations clearly indicated extensive variability in observed residue levels and a high probability of finding an occasional high level in cured tobacco The average residue was 52 mg/kg in flue cured and Burley tobaccos; however, the, data were strongly skewed towards residues in the range 15-60 mg/kg. It would appear that as a guideline level, 100 mg/kg would cover about 96% of all tobaccos examined; 95% would be covered by 200 mg/kg but levels approaching 500 mg/kg were observed. The limited data available showed that neither air curing nor flue curing appeared to alter the level of maleic hydrazide residues found in freshly harvested tobacco leaves; it also appeared unlikely that prolonged storage would lead to any notable reduction in residue levels. Thus, the levels of maleic hydrazide found in freshly harvested or recently cured tobacco leaves can serve as reliable indicators of likely levels at all stages of trade in unblended leaf. The effects of blending, however, are such that the variability of residue level, as well as the levels themselves, are much reduced during the manufacture of cigarettes, cigars, snuff etc. Examination of 16 brands of cigarettes gave a range of residue levels from 22 to 52 mg/kg, with a mean value of 39 mg/kg. Residue levels observed in limited samples of cigars, small cigars, smoking tobacco, chewing tobacco and snuff were, in general, less than those found in cigarettes; the highest level observed was 38 mg/kg, in smoking tobacco. For such tobacco products a guideline level of 50 mg/kg should suffice. Tobacco samples from several countries were analysed by Nesemann, Rabitz and Seehofer (1974). Tobaccos from the USA showed residues of maleic hydrazide ranging from 35 to 94 mg/kg with an average of 65 mg/kg. Two 1969 samples from Italy contained 4 and 11 mg/kg, respectively but other samples from that country and from Argentine, Brazil, Bulgaria, China, Mexico, Philippines and Thailand contained less than 2 mg/kg. Liu and Hoffmann (1973) determined maleic hydrazide in tobacco smoke. They found that cigarettes containing about 30 µ of maleic hydrazide each, yielded smoke containing an average of 1.2 µ g, ie about 4% of the total originally present; hydrazine was not detected in the smoke. A full review of data concerning pesticide residues, including maleic hydrazide, in tobacco and tobacco products was completed recently as part of a study programme of the Directorate-General for Agriculture of the Commission of the European Communities (Anonymous, 1976a,b,c). A draft method for the determination of residues of maleic hydrazide in tobacco and tobacco products is under discussion by the ISO Committee TC 126. Consideration of this procedure has reached an advanced stage and early publication is anticipated. FATE OF RESIDUES In cooking Commercially treated potatoes (3.4 kg a.i./ha) were sampled and analysed for residues of maleic hydrazide (Uniroyal Chemical, 1977a). The potatoes were divided into two parts longitudinally, one half being analysed raw and the other after boiling in water, discarding the liquor and mashing the cooked potato. Table 1 compares the residue of maleic hydrazide found in the raw and cooked potatoes; no significant difference in levels was observed. TABLE 1. Residues of maleic hydrazide in potatoes before and after cooking Sample Treatment to harvest Maleic hydrazide found, mg/kg interval (days) Raw cooked A 65 10 10 B 50 22 20 Recovery of maleic hydrazide added at 20 mg/kg to untreated potatoes was 95%. Samples were analysed by the method of Lane (1963). These findings illustrate the inherent stability of residues of maleic hydrazide to cooking processes. Additionally it has been observed that crops containing maleic hydrazide can be boiled in strong caustic solutions without loss of the residues or its hydrolysis. Under these conditions the addition of zinc is necessary to act as a reducing agent to liberate the hydrazine. No data were available to the Panel concerning the effect on maleic hydrazide residues of different methods of industrial processing in the manufacture of various potato products; the requirement for this information remains. Limited data from treated potatoes showed that free hydrazine did not occur as a residue (Uniroyal Chemical, 1977a). APPRAISAL Residues of maleic hydrazide in harvested potatoes are not diminished on cooking by boiling in water. No information was available regarding other means of cooking or processing. Tobacco treated with maleic hydrazide can contain up to a maximum of 500 mg/kg at harvest and thereafter, no loss occurring during curing or storage; however, 90% of samples will be below 100 mg/kg. Blending and manufacture of tobacco products, eg. cigarettes, cigars, snuff, can reduce observed residues to below about 50 mg/kg. Generally, only 5-10% of the maleic hydrazide in tobacco transfers to the smoke. EVALUATION The following guideline levels can be recorded for tobacco and tobacco products. The guideline level for potatoes is confirmed at 50 mg/kg. Guideline levels are for the sum of free and bound unchanged maleic hydrazide and its B-D-glucoside. Commodity Guideline level, mg/kg Tobacco leaf 100 Tobacco products 50 (cigarettes, cigars, smoking tobacco, chewing tobacco, snuff) FURTHER WORK OR INFORMATION See Report of 1976 Meeting (FAO/WHO, 1977a, Annex 2). Data on the effect of cooking on residues in potatoes and on the carry-over of maleic hydrazide from raw into cured tobacco and into cigarette smoke are no longer required. The other requirements remain. REFERENCES Anonymous. (1976a) Pesticide residues in tobacco and tobacco products. Volume 1. Information on Agriculture, No. 14. Comm. Europ. Commun., Brussels. Anonymous. (1976b) Pesticide residues in tobacco and tobacco products. Volume II. Information on Agriculture, No. 23. Comm. Europ. Commun., Brussels. Anonymous, (1976c) Pesticide residues in tobacco and tobacco products. Volume III. Information on Agriculture, No. 26. Comm. Europ. Commu., Brussels. FAO/WHO (1977a) Pesticide residues in food. Report of the 1976 Joint FAO/WHO Meeting. FAO Food and Nut. Ser., No. 9; FAO Plant Prod. and Prot. Ser., No. 8; Wld. Hlth. Org. techn. Rep. Ser., No. 612. FAO/WHO. (1977b) 1976 Evaluations of some pesticide residues in food. Lane, J.R. (1963) Collaborative study of maleic hydrazide residue analysis. J. Ass. Off. Agr. Chem 46(2): 261-268. Liu, Y-Y. and Hoffmann, D. (1973) Quantitative chromatographic determination of maleic hydrazide in cigarette smoke. Anal. Chem. 45: 2270-2273. Nesemann, E., Rabitz, H. and Seehofer, F. (1974) Methoden zur quantitativen Bestimmug von Boiziden in Tabak. IV Eine Methoden zur Bestimmug von Maleinsäure hydrazide. Beitr. Tabakforsch. 7: 240-243. Uniroyal Chemical. (1977a) Persistence of maleic hydrazide in potatoes. (Unpublished) Uniroyal Chemical. (1977b) Maleic hydrazide residues found in U.S. tobacco. (Unpublished report and review).
See Also: Toxicological Abbreviations Maleic hydrazide (Pesticide residues in food: 1976 evaluations) Maleic hydrazide (Pesticide residues in food: 1980 evaluations) Maleic hydrazide (Pesticide residues in food: 1984 evaluations) Maleic hydrazide (Pesticide residues in food: 1984 evaluations) Maleic hydrazide (Pesticide residues in food: 1996 evaluations Part II Toxicological) Maleic Hydrazide (IARC Summary & Evaluation, Volume 4, 1974)