Bos taurus, milk, pasteurized, homogenized, skimmed, fermented, spray-dried

Endpoint summary

Description of key information

The substance Bos taurus, milk, pasteurized, homogenized, skimmed, fermented, spray-dried (EC 917-734-0) is a UVCB substance originating from biochemical changes produced in milk by various species of bacteria or yeast, where the main constituents are raw proteins (approx. 34.1% w/w), lactose (approx. 40.3% w/w) and lactic acid (=2.5 - =5% w/w); minor constituents include water (3 – 10% w/w), raw ash (inorganic constituents) (>3 – <10% w/w), raw fat (>0.25 – <1.5% w/w), and other carbohydrates (=2 – =3% w/w). Raw ash contains calcium (=7 – =26% w/w), sodium (=0 - =13% w/w), potassium (=13 - =26% w/w) and magnesium (=0 - =13% w/w). The proteins consist mainly of caseines (80%), serum albumines, beta-lactoglobulines, immunoglobulines and lactalbumines.

After ingestion, raw proteins are generally broken down into amino acids through denaturation of the protein in the acidic environment of the stomach and hydrolysis by proteases in the intestine. They are absorbed from the intestine and distributed systemically across various compartments of the body. Since amino acids are of natural origin and form an essential part of the normal human diet, no further consideration of the toxicokinetics of raw protein is necessary

Likewise, ingested lactose is digested through the enzyme lactase, which is expressed in the brush border membrane of enterocytes in the small intestine, and cleaved into the sugar monomers, glucose and galactose which are taken up in the small intestine (Hampson et. al., 1986). Therefore, it is absorbed and distributed as glucose and galactose. Based on the long history dietary human exposure to lactose, the substance is not acute orally toxic and the evaluation of the toxicokinetics of lactose is not considered necessary. Furthermore, lactose is exempted from REACH registration requirements according to REACH Annex IV (substances included in Annex IV: sufficient information is known about these substances that they are considered to cause minimum risk because of their intrinsic properties) and can thus be considered to have non-critical properties.

Due to the low volatility (lactose: <0.1 Pa at 25°C, lactic acid: 11 Pa at 25°C) the main constituents of the substance are not present in a gaseous state and gas-phase absorption through inhalation is therefore highly unlikely at normal ambient temperatures. The 10th percentile and median size of the particles of the substance (D10 = 75.3 µm and D50 = 127.5 µm, mass based) indicates that the large majority of the particles are too big to be inhaled. If some portion of the substance should reach the respiratory tract, the main constituents could cross the alveolar and capillary membranes by a combination of active and passive uptake mechanisms. Additionally, there is human data on the respiratory effects of occupational exposure to milk powder available which, can be used as an analog to provide evidence for yoghurt powder. Although there were no signs of systemic toxicity, increased risk of nasal symptoms, wheezing, breathlessness and reduced spirometric lung function were observed; based on these findings the substance was classified as a Category 1 respiratory sensitizer.

The physical state (solid) and high molecular weight (only <100 g/mol can be readily taken up dermally) of the main constituents suggest that the substance will not be easily absorbed through skin. Additionally, the high water solubility and low log P values (-0.72 to -3.77) will further decrease the penetration into the lipid rich stratum corneum and therefore dermal absorption of the substances will be limited due to high hydrophilicity.. In a worst-case approach, based on the classification of the substance L (+) Lactic Acid (CAS-No. 79-33-4, EC-No. 201-196-2), Bos Taurus, milk, fermented, spray-dried (EC 917-734-0) was classified as “Skin Irritation Cat. 2” (H315). A damaged skin surface, induced through the substance, may enhance the penetration of the substance.

 

Sources:

Hampson, D., Kidder, DE (1986). Influence of creep feeding and weaning on brush border enzyme activities in the piglet small intestine. Res Vet Sci. 40(1):24-31.

Boiling point lactic acid: Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-336

Vapour pressure Lactic acid: Yaws CL; Handbook Chem Compd Data Process Saf, Houston, TX: Gulf Publishing, p. 33 (1997).

Log P Lactic acid: Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society

 

 

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

A toxicokinetic assessment based on the physical properties (see ECHA Guidance on Information Requirements and Chemical Safety Assessment, R7c, version 3.0, June 2017) and toxicity data was performed. NOTE: this is mostly a generic assessment based on general statements in the guidance document that are derived from physical parameters.