1. The Proctor & Gamble Company, Health & Beauty Care Europe, Egham, Surrey TW20 9NW, UK
2. The Proctor & Gamble Company, Miami Valley Laboratories, Cincinnati, OH 45239, USA
3. Unilever Research, Environmental Safety Laboratory, Bedford MK44 1LQ, UK
4. Microbiological Associates Inc., Rockville, MD 20850, USA.