ASM 1999 General Meeting ･Chicago P-30 Compactdry for the Enumeration of Bacteria in Food. S.MIZUOCHI*,H.KAMIYA,H.KODAKA,H.SENGOKU and K.HORIGOME Nissui Pharmaceutical Co.,LTD. 1075-2 Hokunanmoro Yuuki Ibaraki, 〒307-0036 ,Japan Tel: +81-296-35-1225 Fax:+81-296-35-1579 E-mail:mizuochi@dreams.ne.jp Introduction Recently,HACCP programs was introduced in Japan. Food processing companies take a great interest in controlling food safety and quality, microbiological test are carried out more independently. The conventional methods for the enumeration of aerobic bacteria and coliforms from food followed by pour plating on a suitable microbial medium, and so on. For in-house microbial analysis of foods, this type of analysis may be time-consuming(i.e.,requiring media preparation) and more difficult to perform. In this background, Compactdry(NISSUI), ready-to-use and self-diffusible medium system, has be en developed for the enumeration of bacteria. Compactdry consists of special spread sheet with culture media, a cold water soluble gelling agent, and an unique dish. In this study, Compactdry TC was evaluated for the enumeration of total aerobic bacteria from a wide range of foods, as compared to standard plate count method (SPC) and Petrifilm TM Aerobic Count Plates(1). Similarly, Compactdry EC was evaluated for the enumeration of total coliforms from a wide range of foods, as compared to desoxycolate agar(NISSUI), X-Gal agar (NISSUI)(2), XM-G agar (NISSUI), VRBA (Difco) and Petrifilm TM E.coli Count Plates (3). Materials and Methods 1.Organisms A total of 67 strains (32 of gram positive strains, 35 of gram negative strains ) were tested the Compactdry for growth and color reaction to this study. These strains were obtained from culture collections. They were inoculated and grown in Tryptic soy broth (TSB; Difco) at 35 ℃ for 24 hours. Dilution were made to ensure bacterial counts within the range of 30 to 300 colony forming units(cfu)/ each plate. 2.Foods A total of 100 food samples (meat, seafood, confectionery, and delicatessen) analyzed using Compactdry, Petrifilm and conventional pore plate method. 3.Method and procedure Pore plate method : Total aerobic bacterial counts were made by the pour plate method using standard plate count agar (PCA;NISSUI) and total coliform counts were made by the pour plate method with desoxycolate agar(DESO;NISSUI), X-Gal agar (XGal; NISSUI), XM-G agar (XM- G;NISSUI) and VRBA(Difco). Following inoculation, PCA was incubated at 35 ℃ for 48 hours, and total coliform counts agar were incubated at 35℃ for 24 hours, at which time counts were made. Petrifilm TM : Total aerobic bacterial counts were made by Petrifilm TM Aerobic Count Plates (AC;3M,Microbiology Products, St. Paul, MN) and total coliform counts were made by Petrifilm TM E.coli Count Plates (EC). Compactdry : The Compactdry, ready-to-use and self-diffusible medium system, has been developed for the enumeration of bacteria by Nissui Pharmaceutical Co.,Ltd. Compactdry consists of special spread sheet with culture media, a cold water soluble gelling agent, and an unique dish. Total aerobic bacterial counts were made by Compactdry TC and total coliform counts were made by Compactdry EC. The procedure for using Compactdry is shown in Figure 1. Lift the lid and inoculate 1 ml of sample into the center of the dry self diffusible medium. Self diffusion of the sample smoothly. The lid was replaced the unique dish with a memo space. The Compactdry TC incubated for 48 hours at 35 ℃ . The Compactdry EC incubated for 24 hours at 35 ℃. Compactdry TC:All red dots regardless of size or intensity should be counted as colonies. Compactdry EC:Blue colonies confirmed E.coli. The total coliform colonies will be magenta and blue colonies. Figure 1. Procedure for using Compactdry(NISSUI)