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    FAO Nutrition Meetings 
    Report Series No. 48A 
    WHO/FOOD ADD/70.39




    TOXICOLOGICAL EVALUATION OF SOME
    EXTRACTION SOLVENTS AND CERTAIN 
    OTHER SUBSTANCES




    The content of this document is the 
    result of the deliberations of the Joint 
    FAO/WHO Expert Committee on Food Additives 
    which met in Geneva, 24 June  -2 July 19701




    Food and Agriculture Organization of the United Nations
    World Health Organization


                   

    1 Fourteenth report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series in press; Wld Hlth
    Org. techn. Rep. Ser., in press.


    TANNIN (FOOD GRADE)

    Tannic acid was considered at the Tenth Meeting of the Joint FAO/WHO
    Expert Committee on Food Additives but no ADI could be established
    because of insufficient data (FAO/WHO, 1967). Those data and
    additional ones which are summarized below have been reviewed in the
    light of the use of tannins in food processing as a flocculant.

    Biological data

    Biochemical aspects

    None available on food grade material.

    Acute toxicity

                                                                                                  

    Animal   Route            Material          LD50          Reference
                                                mg/kg 
                                                body weight
                                                                                              

    rat      intragastric     Aleppo tannin     1550          Food and Drug Res. Lab. (1964)

             intragastric     Tara tannin       3700          Food and Drug Res. Lab. (1964)

             intragastric     Chinese tannin    2800          Food and Drug Res. Lab. (1965)

             intragastric     Sicilian sumac    2650          Food and Drug Res. Lab. (1967)
                              tannin

             intragastric     Douglas fir       7500          Food and Drug Res Lab. (1967)
                              tannin
                                                                                              
    
    Aleppo tannin stimulated lachrymation and CNS depression. The tannins
    generally appeared to produce motor depression and diarrhoea.

    Short-term studies

          Rat

          Seven groups of 15 males and 15 females received daily either 0,
    8, 80 or 800 mg/kg body weight of Aleppo tannin or tara tannin in
    their diet for 12 weeks. Body weight, food intake and food utilization
    showed no significant changes related to the substance. Liver and
    kidney weights were similar for tests and controls. Gross and
    histopathology showed only incidental abnormal findings unrelated to
    the test substances (Food and Drug Res. Lab., 1964). Similar studies

    at these same levels using Chinese tannin (Food and Drug Res. Lab.,
    1965), Sicilian sumac tannin (Food and Drug Res. Lab., 1967) and
    Douglas fir tannin (Food and Drug Res. Lab., 1967) produced comparable
    findings.

          Dog

          Five groups of 4 males and 4 females received daily 0.0, 0.25,
    0.234, 0.125 or 0.117% Peruvian tara tannin in their diets for 2
    years. Chewing gum containing the tannin at a level of 0.5% was the
    material actually incorporated into the diet, No ill effects were
    noted at any level of tannin fed as judged by behaviour, food
    consumption, haematology, organ function tests, organ weights and
    gross and microscopic pathology (Rosner-Hixon Lab., 1965).

    Long-term studies

          Rat

          Five groups of 50 males and 50 females received daily 0.0, 0.25,
    0.234, 0.125, or 0.117% Peruvian tara tannin in their diets for 2
    years. Chewing gum containing the tannin at a level of 0.5% was the
    material actually incorporated into the diet. No ill effects were
    noted at any level of tannin fed as judged by survival, growth, food
    consumption, haematology, organ weights and gross and microscopic
    pathology (Rosner-Rixon Lab., 1965).

          Three-generation studies, 2 litters per generation, were carried
    out in groups of 20 males and 20 females using Peruvian tara tannin at
    feeding levels of 0.0 and 0.234% and at 0.0, 0.117 and 0.058%. Chewing
    gum containing the tannin at a level of 0.5% was the material actually
    incorporated into the diet. Pups of the group fed at the 0.234% level
    were found to have significantly lower weights at weaning as compared
    to the controls. This effect was not seen at the lower feeding levels,
    nor were effects upon fertility, gestation, viability or lactation
    indices seen at any feeding level (Rosner-Hixon Lab., 1969).

    Comments

          Almost all the early studies on commercial tannin from a variety
    of sources have shown hepatotoxicity. Their relevance to the
    assessment of food grade tannin is small because the presence of
    commercial tannins is excluded by the specification for food grade
    material. Some tannins occurring in natural foodstuffs, such as tea
    and coffee, are not toxic.

          Short-term studies are available on food grade tannins of
    specified origin but only Peruvian tara has been tested in long-term
    studies. While 2-year feeding studies in both dog and rat produced no
    effects at levels up to 0.25%, reduced body-weights at weaning were
    found for rat pups in a multigeneration study at a feeding level of
    0.234%.

    Evaluation

    Level causing no toxicological effects in rats

          1170 ppm (0.117%) in the diet, equivalent to approximately 60
    mg/kg body-weight.

    Acceptable daily intake for man

                                              mg/kg body-weight

        Temporary                                    0-0.6* 

        Temporary                                    0-0.3**

    Further work required by June 1973

          Further information on specifications is required.

          Studies in a second species to demonstrate no increased toxicity
    beyond that shown for Peruvian tara for tannin. derived from Turkish
    Aleppo, Chinese tara and Sicilian sumac.

    REFERENCES

    Anon (1969) Lancet, ii, 34

    FAO/WHO (1967) Wld Hlth Org. techn. Rep. Ser,373

    Food and Drug Research Laboratories (1964, 1965, 1967) Unpublished
    reports submitted to WHO

    Rosner-Hixon Laboratories (1965) Unpublished report submitted to WHO

    Rosner-Hixon Laboratories (1969) Unpublished reports submitted to WHO



                   

    * Derived from Peruvian tara.
    ** Turkish Aleppo, Chinese tara, Sicilian sumac.

    


    See Also:
       Toxicological Abbreviations