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Genetic toxicity: in vitro

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in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:

Materials and methods

Test guideline
according to guideline
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Reference substance name:
Protein hydrolyzates, animal
EC Number:
EC Name:
Protein hydrolyzates, animal
Cas Number:
Molecular formula:
Protein hydrolyzates, animal
Specific details on test material used for the study:
The tested substance is a protein hydrolysate from the GlycoMacroPeptide (GMP) fraction which is derived from cow’s milk. The processed
final product, a supplement or a functional food ingredient, contains high levels of oligopeptides, especially the tripeptide Isoleucine-Proline-Proline (IPP)
The tested substance is known with the commercial name TENSGUARD


Target gene:
Salmonella typhimurium
Escherichia coli
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 mix
Test concentrations with justification for top dose:
The test concentrations ranges from 62 to 5000 ug/plate
Untreated negative controls:
Negative solvent / vehicle controls:
True negative controls:
Positive controls:
Positive control substance:
sodium azide
other: N-ethyl-N-notrosourea and 2-aminoanthracene
Details on test system and experimental conditions:
The bacterial reverse mutation test was performed in compliance with OECD guideline no. 471 using the plate incorporation method with the histidine-requiring Salmonella typhimurium strains TA1535, TA1537, TA98, TA100 and the tryptophanrequiring Escherichia coli strain WP2 uvrA in the absence and presence of a liver fraction of Arochlor 1254-induced rats for metabolic activation (S9-mix). The final concentration of liver homogenate fraction was 10%. Five TensguardTM concentrations were used ranging from 62 to 5000 lg/plate. Negative controls (i.e. the solvent
milliQ water) and positive controls were run simultaneously. The positive control substances were sodium azide (TA1535 and TA100), 9-aminoacridine (TA1537), 2-nitrofluorene (TA98) and N-ethyl-N-nitrosourea (WP2 uvrA) in the absence of S9-mix and 2-aminoanthracene (TA1535, TA98, TA 100 and WP2 uvrA) and benzo(a)pyrene (TA1537) in the presence of the S9-mix. Bacteria were exposed to the substances at 37 C, for approximately 72 h. Toxicity was defined as a reduction (at least 50%) in the number of revertant colonies and/or clearing of the background lawn of bacterial growth. The assay was considered valid if the mean colony counts of the control values of the strains were within acceptable ranges and if the results of the positive controls met the criteria for a positive response (i.e. a two-fold increase compared to the negative control). The test substance was considered to be mutagenic if the mean number of revertant colonies on the test plates was increased in a concentration-related way or if a reproducible two-fold or more increase was observed compared to that of the negative control plates.
Rationale for test conditions:
See prevoius box
Evaluation criteria:
See prevoius box
See prevoius box

Results and discussion

Test results
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
Untreated negative controls validity:
Positive controls validity:

Any other information on results incl. tables

In the bacterial reverse mutation test, TensguardTM was not mutagenic as evidenced by the absence of a dose-related or a more than a two-fold increase in the mean number of revertant colonies compared to the background spontaneous reversion rate observed for the negative control. Furthermore, TensguardTM was not cytotoxic to any strain. The positive control substances gave the expected increase in the number of revertant showing the validity of the test

Applicant's summary and conclusion

The study shows that the tested hydrolysate protein is not genotoxic according to guideline OECD 471