THIABENDAZOLE JMPR 1975
Explanation
Thiabendazole was evaluated by the Joint Meeting in 1970 (FAO/WHO
1971), 1971 (FAO/WHO 1972) and 1972 (FAO/WHO 1973). Tolerances were
proposed for apples, pears, bananas and citrus fruits. Since that time
a considerable amount of information has been obtained on extended
uses for tuber treatment of potatoes and sweet potatoes. Thiabendazole
is used on seed potatoes during storage before planting as well as on
potatoes intended for human or animal consumption to prevent rot
during storage. Some additional data were obtained on residues in milk
of dairy cattle after continuously administering feed containing 10-30
mg thiabendazole/kg. This monograph addendum is an evaluation of the
new data.
USE PATTERN
Registered or considered uses of thiabendazole additional to
those mentioned in previous evaluations are summarized in Table 1.
RESIDUES RESULTING FROM SUPERVISED TRIALS
Potatoes
Extensive data resulting from several trials carried out in
Denmark, the Netherlands and the United States have been examined,
together with limited data from Ireland and the United Kingdom. They
are summarized in Table 2.
FATE OF RESIDUES
In animals
Lactating dairy cattle were fed continuously during 3-4 weeks
with food containing 10, 20 and 30 mg/kg thiabendazole. No residues
were found (limit of determination 0.1 mg/kg) in the milk of cattle
fed 10 and 20 mg/kg. One of 12 milk samples taken from cows fed 30
mg/kg showed an apparent residue of thiabendazole plus its main
metabolites slightly abate the limit of determination (0.1 mg/kg); no
residue was found in the other samples (Warf Inst. Inc., 1974).
In storage and processing
During storage for 3-4 months the initial thiabendazole residue
decreased only slightly. Washing the potatoes before analysis, as in
household practice, resulted in a decrease of 43-73% in the 1974-75
Danish residue trials and 40-77% in the 1973/1974 Netherlands trials
(see Table 2).
TABLE 1. Use patterns of thiabendazole in potatoes, sweet potatoes and sugar beets
Application rate
Country Crop Use Formulation formulation active ingredient Type of treatment
United States seed-potato Only against Suspension 42 fl. oz/100 ca 5g a.i./1000 Spraying on conveyer
of America "edible" fusarium rot 42-45% a.i. gallon kg potatoes band, sometimes followed
potatoes 1 gallon/metric by dipping in the same
tonne potatoes concentration
wp 60% 2 pounds/100 ca 5g a.i./1000 "
gallon kg potatoes
1 gallon/metric
tonne potatoes
Denmark seed- Rot caused by suspension 4.7 l/100 litre ca 42g a.i./ spraying on
Federal potatoes black scurf 42-45% a.i. 2 litre/metric 1000 kg conveyer band
Republic of Rhizoctonia tonne potatoes or swing-fog
Germany solani potatoes treatment of
skin spot storage bins
Netherlands Oospora postulans
silver scurf wp 60% 3.5 kg/100 l ca 42 gr a.i./ "
Helminthosporium 2 litre 1000 kg
solani suspension/metric
tonne potatoes
gangrene smoke
Phoma exigua tablets 12% ca 40g a.i./
1000 kg
United States sweet- Black rot suspension 110-130 fl. oz/ root dip
of America potato scurf 42-45% a.i. 100 gallon
(seed roots) foot rot
sugar beet Cercospora leaf suspension 6-12 fl. oz/ 0.3-0.6 kg/ha spraying of
spot 42-45% a.i. acre aerial parts
wp 60% 5-10 oz/acre 0.3-0.6 kg/ha " "
TABLE 2. Thiabendazole residues in potatoes resulting from supervised trials
Residues, mg/kg
Country Application
(references g a.i. Storage Unwashed Washed
in metric period, Whole edible Whole edible
Crop parenthesis) Year No. tonne Formulation months potato peel portion potato peel portion
Potatoes Denmark 1974/ 1 40 wp 60% 0 2 2.8 10.3 0.07*
(edible) (Holm, 1975 Mist spray
Bintje 1975) 1 5.9 36.8 0.05 1.6 9.5 0.02
2 5.9 33.8 0.06
1 40 smoke tablet 0 10.8, 10.0 46.0, 49.2 0.50, 0.15
12% 1 9.8, 8.9 50.5, 42.3 0.07, 0.22 4.0, 4.7 21.7, 25.8 0.04, 0.07
2 7.9, 6.4 43,1, 35.4 0.21, 0.08
1 40 Pulsfog 0 10.6, 6.7 56.1, 33.9 0.09, 0.14
form 1 6.9, 5.7 37.3, 31.0 0.19, 0.10 3.9, 0.6 18.9, 8.7 0.08, 0.05
2 10.2, 5.1 57.5, 27.2 0.16,0.07
Kennebeck 1974/ 1 wp 60% 0 4.6 25.2 1.9
1975 Mist spray
1 0 5.0 43.9 0.32
Desire 1 0 2.7 18.2 4.3
Ireland 1974 1 42 wp 60% 9.22
(Logan, 1974; Mist spray (8.45-13.3)
Merck, Sharp
and Dohme,
1974 b)
United Kingdom 1972/ 1 ca 45 dust 1% 2.3**
(Tisdale and 1973
Lord, 1973) 1 ca 225 dust 5% 4.8**
TABLE 2. (Cont'd.)
Residues, mg/kg
Country Application
(references g a.i. Storage Whole Unwashed potatoes
in metric period, washed whole edible Ratio: Notes
Crop parenthesis) Year No. tonne Formulation months potato potato peel part peel:
edible
part
Potatoes Netherlands 1973/ 1 25 suspension 0 2.71 41.8 0.27 1:16
(Merck, Sharp 1974 42-45.1%
and Dohme, 6 0.74 3.18 14.9 *** 1:4.8
1974c, 1975) 25 wp 30-40% 0 2.07 31.2 0.25 1:16
acid form
1 25 Wäcker form 0 1.87 25.2 0.41 1:16
15%
2 25+25 suspension 0 1.75 3.51 75. *** 1:16
42-45% 4.5 0.54 0.93 5.14 0.04 1:4.8 Average whole
(0.23-0.78) (0.89-1.01) (4.75-5.60) (0.02-0.10) pile and range
6 1.02 2.01 9.1 0.53 1:4.8 Top layer of
pile
2 25+25 wp 30-40% 0 2.09 3.51 5.10 0.54 1:16 Average whole
acid form (0.81-1.29) (1.43-2.24) (6.45-10.8) (0.33-0.57) 1:4.8 pile and range
6 0.90 2.22 10.9 0.41 1:4.8 Top layer of
pile
2 25+25 Wäcker form 0 0.76 2.21 22.0 *** 1:16
15%
4.5 1.44 2.86 14.9 0.37 1.4.8 Average whole
(0.79-1.70) (1.41-3.78) (7.5-21.6) (0.07-0.69) 1.4.8 pile and range
6 2.05 3.00 16.0 0.29 1.4.8 Top layer only
3 3×25 Suspension 2.5 1.62 4.16 14.5 *** 1.4.8
3 3×25 wp 30-40% 2.5 1.90 3.58 19.2 0.32 1.4.8
acid form
3 3×25 Wäcker form 2.5 2.84 5.38 26.0 1.09 1.4.8
15%
1974/ 1 10 suspension 0.13
1975 45%
Pulsfog
TABLE 2. (Cont'd.)
Residues, mg/kg
Country Application
(references g a.i. Storage Whole Unwashed potatoes
in metric period, washed whole edible Ratio: Notes
Crop parenthesis) Year No. tonne Formulation months potato potato peel part peel:
edible
part
Potatoes Netherlands 1974/ 1 10 suspension 0.39
(Merck, Sharp 1975 45%
and Dohme, Mist spray
1974c, 1975) 10 Dust, thermal 0.32
dusting
application
Prior to treatment
Storage Unwashed
period
w=weeks washed prior
m=months Unwashed Washed to analysis
Potatoes United States 1972 1 5.5 wp 60% 1 w 1.16-1.30 0.01-0.02
(Merck, Sharp 10.5 wp 60% 1 w 2.16-2.30
and Dohme,
1974a)
Russet 5.5 wp 60% 11 m 0.97-1.01
Burbank 10.9 wp 60% 11 m 1.13-1.15
2.7 wp 60% 11 m 1.48-2.53 0.97-1.02
5.5 wp 60% 11 m 1.63-2.87 1.41-1.44
10.9 wp 60% 11 m 1.85-3.00 0.16-0.17
5.5 wp 60% 1-1/2 w 1.62-1.65 0.75-0.77
24-29 w 1.40-1.66
10.9 wp 60% 1-1/2 w 2.94-3.06 1.36-1.37
24-29 w 3.37-3.41
TABLE 2. (Cont'd.)
Residues, mg/kg
Country Application
(references g a.i. Storage Whole Unwashed potatoes
in metric period, washed whole edible Ratio: Notes
Crop parenthesis) Year No. tonne Formulation months potato potato peel part peel:
edible
part
Monona and
Russet 1973 1 5.5 suspension 1-1/2 w 0.45-0.56 0.36-0.46
Burbank 40% wp
10.9 " 1-1/2 w 0.91-1.54 0.40-0.88
5.5 " 5 w 0.44-0.52 0.40-0.52
10.9 " 5 w 0.90-1.18 0.45-1.07
5.5 " 11 w 0.49-0.52 0.40-0.72
10.9 " 11 w 0.90-1.18 0.45-1.16
5.5 " 22 w 0.69-0.40 0.48-0.52
10.9 " 22 w 0.95-1.66 0.6 -0.88
5.5 " 30 w 0.44-0.60 0.44-0.48
10.9 " 30 w 0.83-1.22 0.58-1.00
* Samples erroneously washed before analysis.
** Dust removed by brushing before analysis.
*** Sample analysis unreliable.
The remaining residue occurred mainly in the skin. It was shown
in an experiment carried out in Idaho, United States of America, in
1974 (Merck, Sharp and Dohme, 1974d) that further processing to French
fries, especially peeling, removed most of the remaining residue
(Table 3).
TABLE 3. Effect of processing on thiabendazole residues in potatoes
Thiabendazole residues, mg/kg
Potatoes and potato products
French Waste
After fries Trim Caustic
caustic After not table waste
Unwashed Washed treatment peeling fried In peel waste liquid
1.44 1.00 0.23 0.02 0.01 2.50 0.16 0.02
3.41 2.10 0.40 0.03 0.01 5.28 0.16 0.12
NATIONAL TOLERANCES REPORTED TO THE MEETING
National tolerances established or changed since the 1972 Joint
Meeting (other than tolerances on apples, pears, bananas and citrus
fruits) are listed in Table 4.
TABLE 4. National tolerances reported to the Meeting
Tolerance,
Country Commodity mg/kg
Australia meat 0.2
milk 0.05
Israel celery 5
strawberries 3
Netherlands tomatoes 0.1
United potatoes (from post harvest applications) 3
States of milk, fat, meat and meat by-products of
America cattle, goats, hogs, horses and sheep 0.1*
sugar beet (excluding tops) 0.25
sugar beet tops 10
dried or dehydrated sugar-beet pulp 3.5
* Combined residue of thiabendazole and 5-hydroxythiabendazole
ref: USA Fed. Reg. 1975.
APPRAISAL
Extensive data became available from the United States, Denmark
and the Netherlands together with some from Ireland and the United
Kingdom on the use of thiabendazole on potato tubers and residues
resulting therefrom.
Some additional data on the residues in milk after feeding cows
with feed containing 10-30 mg/kg of thiabendazole were evaluated. No
residues were found (limit of determination 0.1 mg/kg) in milk of
dairy cattle fed continuously for 3-4 weeks on feed containing these
residue levels.
Data from supervised trials on the residues in seed potatoes and
edible potatoes were evaluated. Since seed potatoes may be used to
some extent for human consumption or as animal feed the establishment
of a maximum residue level is desirable.
The dosage rates applied in the United States are considerably
lower than those applied in some European countries. In the latter the
treatment is used to control a larger number of tuber diseases, some
of which require higher dosage rates.
The amount of the initial residue after treatment depends largely
on the dosage rates applied, the type of formulation, the method of
application and the amount of adhering soil. Since the residue remains
mainly on the skin however, household washing and especially peeling,
decreases the residues remaining after storage to very low levels.
Industrial processing involving washing and/or brushing reduced
residues in the tubers to levels at or about the limit of
determination.
National tolerances have been established in some countries for
thiabendazole on or in potatoes and in products of animal origin.
Since maximum residue limits for pesticides are established in
various countries on either unwashed or washed potatoes, and since
washed potatoes are an item of international trade, it is desirable to
establish limits on both unwashed and washed potatoes.
RECOMMENDATIONS
In the light of the new data and data previously available, the
following additional maximum residue limits are recommended. They
refer to thiabendazole + 5-hydroxythiabendazole, expressed as
thiabendazole.
MAXIMUM RESIDUE LIMITS
Limit,
Commodity mg/kg
Potatoes (unwashed) 10
Potatoes (washed) 3
Milk, meat and meat products of
cattle, goats, horses, pigs and
sheep 0.1*
* At or about the limit of determination of combined residue of
thiabendazole and 5-hydroxythiabendazole.
FURTHER WORK OR INFORMATION
DESIRABLE
1. Data on current use patterns to various countries,
especially on pre-harvest uses, and on resulting residue levels
including those on grain crops, strawberries and tomatoes.
REFERENCES
Holm, F. (1975) Rapport over restkoncentrationer af thiabendazole i
Kartofler. rep, Bioteknisk Institut, Kolding Danmark for Merck Sharpe
& Dohme.
Logan, C. (1974) Potato tuber disinfection by Thiabendazole Mist
Application. Agriculture in Northern Ireland, 48:439-440.
Merck, Sharp and Dohme. (1974a) Residue data in the petition for
registration in the USA of the pesticide chemical thiabendazole on raw
agricultural chemicals; White potato, 28 June 1974.
Merck, Sharp and Dohme. (1974b) Residue analysis by Merck, Sharp &
Dohme Ltd, Hodderson, England on samples of treated potatoes from 1974
trials by Dr Logan. Dept. of Agr. Belfast, N. Ireland. Unpublished
report, Merck, Sharp & Dohme.
Merck, Sharp and Dohme. (1974c) Residue data on potatoes after
treatment with thiabendazole; data generated from 1973-1974 trials in
Holland with analysis made by Merck, Sharp & Dohme. Unpublished report
of Merck, Sharp & Dohme.
Merck, Sharp and Dohme. (1974d) Commercial processing of thiabendazole
treated Russett Burbank potatoes into French fries; 1974 Idaho
experiment. Data in the Petition for registration in the USA of the
pesticide chemical thiabendazole on raw agricultural commodities.
White potato, 28 June 1974.
Merck, Sharp and Dohme. (1975) Residue limits (from the Netherlands)
on potatoes treated with various methods of application of
thiabendazole and washed before analysis. Unpublished report Merck,
Sharp & Dohme.
Tisdale, M. J. and Lord, K. A. (1973) Uptake and distribution of
thiabendazole by seed potatoes. Pesticide Science, 4:121-130.
USA Fed. Reg. (1975) Fed. Register Vol. 40 No. 117, Tuesday 17 June
1975. Tolerances for thiabendazole in or on raw agricultural
commodities.
Warf Inst. Inc. (1974) Thiabendazole studies on residues in milk of
dairy cattle fed thiabendazole continuously in feed. Report Warf Inst.
Inc. for Merck, Sharp & Dohme in the Petition for registration in the
USA of the pesticide chemical thiabendazole on raw agricultural
commodities; white potato, 28 June 1974.
See Also:
Toxicological Abbreviations
Thiabendazole (WHO Food Additives Series 39)
Thiabendazole (AGP:1970/M/12/1)
Thiabendazole (WHO Pesticide Residues Series 1)
Thiabendazole (WHO Pesticide Residues Series 2)
Thiabendazole (Pesticide residues in food: 1977 evaluations)
Thiabendazole (Pesticide residues in food: 1979 evaluations)
Thiabendazole (Pesticide residues in food: 1981 evaluations)