A comparison of contact plate and calcium alginaie swab techniques for quantitative assessment of bacteriological contamination of environmental surfaces

Abstract

S cott , E. B loomfield , S.F. & B arlow , C.G. 1984. A comparison of contact plate and calcium alginate swab techniques for quantitative assessment of bacteriological contamination of environmental surfaces. Journal of Applied Bacteriology 56 , 317–320. A contact plate method for enumeration of bacteriological contamination at 9 environmental sites in 64 homes was compared with swab sampling techniques. Contamination levels of 100 or more organisms/21–25 cm 2 were demonstrated more frequently using swab methods, but for some sites where low numbers of organisms were present, higher recovery rates were obtained using contact plates. When contamination levels from contact plate and swab techniques were compared according to rank order a good correlation was obtained. Results of this investigation indicate that the contact plate method is satisfactory for differentiation of ‘hygiene levels’ at environmental sites whilst facilitating handling of large numbers of samples in a field survey.