Bacterial Adherence: Its Consequences in Food Processing

Abstract

The adherence of bacteria to various substrates is well known. The results of the attachment of contaminating bacteria to glass, plastic or metal surfaces in food processing equipment can have serious consequences during a food processing run and with any subsequent cleaning and sanitizing procedures. If these procedures are inadequate, considerable numbers of viable bacteria may remain. Even with cleaning procedures which appear satisfactory, studies using epifluorescent microscopy and scanning electron microscopy (SEM) have shown that low numbers of organisms can survive and remain attached. Standard bacteriological methods, which are used to evaluate the efficiency of a cleaning procedure, may not be capable of detecting low numbers of organisms adhering to a surface. This has been demonstrated by epifluorescent microscopy on food contact surfaces. Bacteriological techniques such as swabs or contact plates are slow in yielding results compared to such procedures as direct epifluorescent microscopy, which enables enumeration and demonstration of viability of organisms remaining on a food contact surface in less than thirty minutes. The development of fast, reliable and sensitive methods for the detection and enumeration of viable bacteria on food contact surfaces is important, so that bacteriological monitoring of cleaning and sanitizing procedures in the food processing industry can be maintained during, and not considerably after, a food processing run.