GLUCOSE ISOMERASE (IMMOBILIZED) FROM STREPTOMYCES OLIVOCHROMOGENES

    EXPLANATION

         This substance has not been previously evaluated by the Joint
    FAO/WHO Expert Committee on Food Additives.

    BIOLOGICAL DATA

    Biochemical aspects

         No information available.

    Toxicological studies

    Acute toxicity

         No information available.

    Short-term studies

    Rats

         Groups of 15 male and 15 female Charles-River albino rats were
    fed 0, 1, 3, or 10% of a preparation of whole S. olivochromogenes
    cells in the diet for 90 days. Harvesting of the cells for the feeding
    studies was performed by the addition of 36 g/litre of Perlite to the
    fermentation media followed by filtration and washing. (A semipurified
    enzyme preparation from lysed cells - no Perlite added - is used in
    the actual commercial production of high fructose corn syrup.) An
    additional group of 15 males and 15 females were fed a diet containing
    7.5% Perlite for 90 days. Clinical chemistry, haematology, urinalysis,
    and microscopic pathology were conducted on 10 animals/sex from the
    control, Perlite, and high-dose groups.

         There was a small decrease in liver to body-weight ratio in all
    treatment groups and in the Perlite groups. The decreases were not
    dose-related. Spleen to body-weight ratios were decreased in mid- and
    high-dose females, but the magnitude of the effect was small. There
    was an increase in ovary to body-weight ratio in low- and high-dose
    females, but there was an inverse dose relationship and the magnitude
    of the effect was small. No treatment-related changes were reported
    with respect to body-weight gain, food consumption, haematology,
    clinical chemistry, urinalysis, or gross or microscopic pathology
    (Smith, 1972).

    Dogs

         Groups of 4 male and 4 female beagle dogs were fed diets
    containing 0, 1, 3, or 10% of a S. olivochromogenes whole-cell
    preparation similar to that described above in the rat study. An
    additional group of 4 males and 4 females were fed a diet containing
    7.5% Perlite. A significant reduction in body-weight gain was observed
    in the male high-dose group. No statistically-significant effects of
    treatment on food consumption were reported, but there appeared to be
    a dose-related trend toward lower food consumption in females. An
    increased brain to body-weight ratio in high-dose and diluent-control
    males was probably due to the reduced body-weight gain in these
    groups. No significant treatment-related changes were reported with
    respect to haematology, clinical chemistry, urinalysis, or gross or
    microscopic pathology (Burtner, 1972).

    Comments

         Short-term feeding studies in rats and dogs showed no significant
    toxicological effects. Although the preparation fed in these studies
    differs from that used in commercial preparations, the high levels of
    whole cells fed (up to 10% of the diet) plus the use of a Perlite
    control provide adequate information for evaluating the safety of the
    preparation derived from lysed cells.

    EVALUATION

    Level causing no toxicological effect

    Rat: 10% (100,000 ppm) in the diet, equivalent to 10,000 mg/kg
         b.w./day.

    Estimate of acceptable daily intake for man

    Acceptable for use in food processing when used as a component in an
    immobilized system.

    REFERENCES

    Burtner, B.R. (1972). Ninety-day subacute oral toxicity study with
         XSO-1228 in Beagle dogs. Unpublished report of Industrial
         BIO-TEST Laboratories, Inc. Submitted to the World Health
         Organization by CPC International, Inc. (validated study).

    Smith, P.S. (1972). Ninety-day subacute oral toxicity study with XSO
         1228 in albino rats. Unpublished report of Industrial BIO-TEST
         Laboratories, Inc. Submitted to the World Health Organization by
         CPC International, Inc. (validated study).
    

    See Also:
       Toxicological Abbreviations