ETHYL LACTATE

    Explanation

         This substance was evaluated for acceptable daily intake for man
    (ADI) by the Joint FAO/WHO Expert Committee on Food Additives in 1967
    and 1979 (see Annex I, Refs. 14 and 51). Toxicological monographs were
    issued in 1967 and 1979 (see Annex I, Refs. 15 and 52).

         Since the previous evaluation, additional data have become
    available and are summarized and discussed in the following monograph.

         The previously issued monographs have been expanded and are
    reproduced in their entirety below.

    BIOLOGICAL DATA

    BIOCHEMICAL ASPECTS

         Substantial evidence has accumulated that simple esters readily
    undergo enzymatic hydrolysis into their component acids and alcohols
    (FEMA, 1974; Longland et al., 1977; Grundschober, 1977). It can be
    presumed that ethyl lactate is readily hydrolysed in the body to ethyl
    alcohol and lactic acid, both of which are common food constituents
    (Fassett, 1963).

         Aqueous solutions of ethyl-L-lactate, containing 1 mg of
    ester/ml, were incubated at 37° in a 0.05 N phosphate buffer, pH 7.5,
    with or without pancreatin or a porcine small intestinal mucosa
    preparation. The chemical hydrolysis of ethyl-L-lactate was found to
    be less than 2% during 2 h; with pancreatin less than 7% was
    hydrolysed in 1 h and 7-9% in 2 h; with the intestinal mucosa
    preparation these figures were 48-56% and 73-86%, respectively
    (Leegwater and van Straten, 1979). Thus it is likely that ethyl
    lactate is readily hydrolysed in the body to ethyl alcohol and L(+)
    lactic acid, both of which are common food constituents.

         The metabolic fate of ethyl alcohol is well-known (FEMA, 1974)
    and lactic acid is, of course, a normal and essential intermediate in
    human metabolism (Oser, 1965). The metabolism of lactic acid has been
    studied extensively, both in humans and in other mammals (Informatics,
    Inc., 1975; FEMA, 1977).

    TOXICOLOGICAL STUDIES

    Acute toxicity

         None available.

    Short-term studies

    Rat

         Ethyl lactate was reportedly a good energy source and enhanced
    growth in a group of eight male weanling rats fed a diet containing 5%
    of this ester (approximately equivalent to 5 g/kg bw) over a period of
    12 days. One of eight animals died during the course of the experiment
    (there was no indication of the cause of death). No adverse effects
    were observed in the surviving animals (Yoshida et al., 1971).

    Long-term studies

         None available.

    Comments

         Previously it was concluded that this substance was probably
    hydrolysed in vivo to lactic acid and ethyl alcohol. Data have
    become available on in vitro hydrolysis. The temporary allocation of
    ethyl alcohol to the group ADI "not specified" for lactic acid has
    been extended.
    

    EVALUATION

    Estimate of temporary acceptable daily intake for man

    Group ADI for lactic acid: "ADI not specified".*,**

    FURTHER WORK OR INFORMATION

    Required by 1982

         An in vivo hydrolysis study.

              

    *    The statement "ADI not specified" means that, on the basis of the
         available data (toxicological, biochemical, and other), the total
         daily intake of the substance, arising from its use or uses at
         the levels necessary to achieve the desired effect and from its
         acceptable background in food, does not, in the opinion of the
         Committee, represent a hazard to health. For this reason, and for
         the reasons stated in individual evaluations, the establishment
         of an acceptable daily intake (ADI) in mg/kg bw is not deemed
         necessary.

    **   Temporary.
    

    REFERENCES

    Fassett, D.W. In: Patty, F. A., ed., Industrial hygiene and
         toxicology, second edition, Interscience, New York and
         London, 1963

    FEMA. Scientific literature review of aliphatic primary alcohols,
         aldehydes, esters, and acids in flavor usage, published by the
         National Information Services under Contract with the Food and
         Drug Administration, 1974

    FEMA. Scientific literature review of propylene glycol, glycerol and
         related substances in flavor usage, published by the National
         Information Services under Contract with the Food and Drug
         Administration, 1977

    Grundschober, F. Toxicological assessment of flavouring esters,
         Toxicology, 8, 387-390, 1977

    Informatics, Inc. Scientific literature reviews on generally
         recognized as safe (GRAS) food ingredients. Lactic acid, US Food
         and Drug Administration, Washington, D.C., 1975

    Leegwater, D. C. & van Straten, S. In vitro study on the hydrolysis
         of ethyl-L-lactate by pancreatin and an intestinal mucosa
         preparation. Unpublished report from TNO, Zeist, submitted to the
         World Health Organization by C.V. Chemie Combinatie Amsterdam
         C.C.A. Gorchem, The Netherlands, 1979

    Longland, R. C., Shilling, W. H. & Gangolli, S. D. The hydrolysis of
         flavouring esters by artificial gastrointestinal juices and rat
         tissue preparations, Toxicology. 8, 197-204, 1977

    Oser, B. L. Physiological chemistry, McGraw-Hill Book Company, 1965

    Yoshida, M., Ikumo, H. & Suzuki, O. Evaluation of available energy of
         aliphatic chemicals by rats: an application of bioassay of energy
         to monogastric animal, Agr. Biol. Chem., 35(8), 1208-1215,
         1971
    

    See Also:
       Toxicological Abbreviations
       Ethyl lactate (FAO Nutrition Meetings Report Series 44a)
       Ethyl lactate (WHO Food Additives Series 14)
       ETHYL LACTATE (JECFA Evaluation)