MICROBIOLOGICAL PROFILE OF COSMETICS Table VI Microbiological Profile of a Liquid Eyeliner, with and without Preservatives, after Use 869 Plate Count s Isolation From Enrichment b No. of Upon After 3 Upon Preservative a Subjects collection months collection After 3 months None 10 8 = 10/g 9 = 100/g Staph 2 = TNTC 1 = TNTC Gram bacilli 0.075% MeP 8 N.R. N.R. 5 = N.R. 0.04% PP 3 = staph 0.2% MeP 10 N.R. N.R. N.R. 0.1% PP Staph Gram q- bacilli, mold 7 = N.R. 1 = mold N.R. a MeP = methyl paraben PP = propyl paraben. b N.R. = no recovery TNTC = too numerous to count. of eyeliners were prepared as follows: unpreserved with 0.075% methyl and 0.04% propyl paraben with 0.2% methyl and 0.1% propyl paraben. The second group represented a marginal or possible subopti- mum preservative level. Table VI shows that after use, the unpreserved liner had a plate count of from 10/g to TNTC. The product containing the low preservative level and the higher preservative level had negative plate counts immediately after use and 3 months after use. After enrichment streaking on differential media, the unpreserved samples showed the presence of gram-positive bacilli and Staphylococcus. Enrichment of the product containing the low preservative level showed Staphylococcus in two units and coagulase q- staphylocci from one unit. All other units were negative. After 3 months, the unpreserved units which had less than 10/g immediately after use were less than 100/g. Another unit went from TNTC to 130/g. One of the units which was TNTC upon collection remained TNTC after 3 months. The enrichment procedure showed recovery of gram-positive bacilli and mold in all unpreserved units. For the low preservative product, the enrichment procedure showed that one unit contained only fungi 3 months after use. All units containing the higher preservative level showed no recovery after 3 months. Emulsion Products The facial cleanser cream was a relatively high oil (45%), nonionic, oil-in-water emulsion supplemented with 5% of a natural ingredient (avocado oil). The pH was 5.9. The preserved product contained

870 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table VII Microbiological Profile of an Oil-in-Water Nonionic Emulsion Cream Face Cleanser after Use Plate Cotrot a Isolation From Enrichment a No. of Upon After 3 Upon After 3 Preservative Subjects collection months collection months None 5 1-3 = N.R. N.R. N.R. N.R. 4 = N.R. N.R. Gram q- bacilli N.R. 5 -- N.R. N.R. Staph N.R. 0.3% Preservatol 5 N.R. N.R. N.R. N.R. • N.R. = no recovery. 0.3• Preservatol©. * Interestingly, the used unpreserved facial cleanser (Table VII) showed a negative plate count upon collection and only two units had microorganisms recoverable by enrichment. After 3 months, we were not able to repeat this recovery. The used preserved units showed negative plate counts and no recovery upon enrichment. Laboratory inoculation studies with this unpreserved facial cleanser cream showed the formula to be very resistant to microbial growth. The moisture lotion was also nonionic and an oil-in-water emulsion. The pH was 7.0. It had total oil content of 10%, one third of which was avocado oil. The preservative was 0.2% Dowicil 200©.t Results are shown in Table VIII. The unpreserved product was very susceptible to microbial contamination. Pseudomonas, Sarcina, and yeasts were re- covered from used units. Ultimately, all used unpreserved samples were very odorous and unacceptable. However, the used preserved sample was adequately protected. The night cream was a nonionic, oil-in-water emulsion containing 45% oil. The pH was 6.9. It contained 10% of fluid skim milk. The preservatives were 0.2% methyl and 0.1% propyl paraben and 0.01% Bronopol ©. { Table IX shows the results. Three of the 5 used samples had no plate count even 3 months after use. Two were lightly con- taminated with staphylococci, mold, and gram-positive bacilli. One sample showed a higher count upon collection and in 3 months was populated with staphylococci, coliform, and yeast. The use preserved units were adequately protected. * Van Dyk and Co., Belleville, N.J. t Dow Chemical Co., Midland, Mich. :• Boots Pure Drug Co., Nottingham, England.