Study of contact plates recovery from pharmaceutical cleanroom surfaces across three-time ranges

Abstract

Viable environmental monitoring methods remain primarily culture based. One example is with the contact plate. While the method is long-established, there remain aspects that are under-researched in relation to sampling. Factors affecting surface recovery relate to microbial adhesion, the type of surface, the sampling method and the time and pressure applied. This paper examines the effect of time, when a consistent pressure is applied, in relation to microbial recovery (for the organism Staphylococcus aureus) from two surfaces common to pharmaceutical facilities: stainless-steel and vinyl. The experimental results show that surface recovery was superior for vinyl compared with stainless-steel. For both surface types, a 20 second sampling time was shown to lead to a better recovery compared to a ten second sampling time (with a 30 second sampling time not leading to a significant improvement to the microbial surface recovery).