A comparison of incubation periods for bioburden isolates

In recent years, bioburden testing of health care products has gained importance for overall quality assurance and compliance purposes. ISO 11737-1 has a section that addresses incubation periods, accompanied by a chart providing a range of days for each general type of bioburden test. Incubation ranges are 2 to 5 days for aerobic bacteria, 5 to 7 days for fungi, and 3 to 5 days for anaerobic bacteria. If one develops a bioburden test using only the lower end of each incubation range, that shorter incubation period may not be sufficient to detect the types of organisms associated with health care products. This study was developed to determine the impact of incubation time on the determination of bioburden levels on typical health care products. Based on the results, it was determined that in order to accurately enumerate the product bioburden, a significant portion of the health care products required bioburden incubation periods beyond 3 days for aerobic counts and beyond 5 days for fungi counts.