216 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 60 50 40 30 20 10 high body odor HGQ TCC HGQ TCC [• better product •7• no difference • blank sample better Figure 2. Comparison of the deodorant effect of soaps containing either a natural active substance mixture (HGQ) or TCC (0.26%), solubilized with nonylphenolethoxylate 9 (24) (x = statistically significant difference). Table II Sniff Test: Sniff Potential Assessment Scale 0 Fresh, pleasant odor (faint scent of perfume, conditioner) 1 Fresh, pleasant odor 2 Faint musty odor 3 Unpleasant, distinctly musty odor 4 Unpleasant, faint odor of sweat 5 Unpleasant, strong odor of sweat P Strong perfume masking everything else The sniff potential is assessed by three experts. latter two substances were widespread, especially in the deodorant sector, and served as the standards (4). Biological degradability is tested by measuring the amount of oxygen required for oxidation. A distinction is made between the chemical oxygen demand (COD) and the biological oxygen demand (BOD). Chemical oxygen demand is a constant and corresponds to the amount of chromium(VI) compounds--expressed as oxygen relative to a 1-1iter sample of water--consumed under defined conditions by the reducing components of contaminated water. Biological oxygen demand is defined as the amount of oxygen required by microorgan- isms from activated sludge basins for oxidative degradation of the organic substances

GROWTH INHIBITION OF CORYNEFORM BACTERIA 217 Table III Results of a Comparison of Three Spray Preparations Product A: contains 2,4,4'-trichloro-2'-hydroxydiphenyl ether (0.26%, solubilized) Product B: contains HGQ (0.3%) Product C: placebo Sniff test AB 6 h: no difference in sniff potential AB 12 h: no difference in sniff potential A)(B 24 h: no difference in sniff potential Self-assessment Evaluation of the questionnaire revealed that the subjects reported no preference for either of the two products. Sniff test B)(C 3 h: B significantly better than C in sniff potential B)(C 12 h: B significantly better than C in sniff potential B)(C 24 h: B significantly better than C in sniff potential Self-assessment Evaluation of the questionnaire revealed: After 3 h and 12 h the subjects clearly preferred B. After 24 h the subjects reported that B seemed more effective. contained in a i-liter water sample under given test conditions (time, temperature, etc.) (23). The BOD subscript indicates the test period in days. The BOD5/COD ratio is often formed, which represents the relative biological degradability. The results of these types of test are naturally subject to variations. The information obtained on the degradation behavior, i.e., return of the component substance to the natural cycle, does, however, allow an estimation of the impact on the environment. Two grams of each product were mechanically shaken for 24 hours, the undissolved fraction separated, and the chemical and biochemical oxygen demand of the dissolved components determined. For this reason, the results are not related to the product itself but to the aqueous solution prepared as described. The data permit estimation of the degradability on the basis of the BOD5/COD ratio (4). Table IV shows that the soluble fraction of 2,2'-methylenebis(6-bromo-4-chlorophenol) has a very poor biological degradability. For 2,4,4'trichloro-2'-hydroxydiphenyl ether there is apparently a total inhibition of degradation by the microbiocidal effect. The natural product active substances named above have an acceptable degree of de- gradability. The degradation products are only CO 2 and H20 , as HGQ does not contain any nitrogen. (Also see Figure 3.) Furthermore, this finding indicates that although the synergistically acting HGQ mixture has a selective bactericidal effect, it is degraded naturally after use, which is not true of the first deodorant generation. DISCUSSION A major component of odor production is eliminated by growth inhibition of coryne- form bacteria. It seems probable that the coryneform bacteria do not themselves produce