An environmental monitoring program… why is it so important? The objective of this program and specifically the sampling/swabbing is to seek and eliminate harborage sites. Don’t be afraid to find pathogens, you should be looking for them! Make a habit of trending positives over long periods of time, as it will help you tremendously in finding and solving the source of your sporadic finds.
If you follow a couple of simple guidelines, you will see an immediate improvement in sampling/swabbing effectiveness, and increase your likelihood of detecting niches before a pathogen contaminates your products. We have summarized them in three categories for you:
Share these tips with your team to move your environmental monitoring program to the next level.
Sampling and Sample Handling
Sampling should be done aggressively by covering a large surface and targeting sites that are most likely to be contaminated. For practical purpose, it is generally recommended that for smooth and large surface, a minimum 12×12 inches (30x30cm) should be swabbed; for small or irregular surfaces, using a cotton-tip swab or rinsing the surface/crevices and analyzing the rinsate may be appropriate.
To verify the effectiveness of controls/barriers, it may be more indicative to sample larger surfaces than the regular 12 x12 inches (30 x30 cm). For example, to verify the effectiveness of a footbath or door foamer, it may be more indicative to sample a surface the width of the footbath by the length of a stride, instead of a 12 x 12 inches surface. Another example is to sample periodically cleaned equipment/areas before and after cleaning to verify the cleaning frequency and its effectiveness. Keep in mind that sampling is to seek and eliminate the harborage sites.
Swabbing should cover the areas completely following the pattern of horizontal, vertical, and diagonal directions. In dry facilities, it is also recommended to sanitize the area using alcohol spray after sampling or dry the area with alcohol wipe to remove the excess moister left from the sampling devices. The technician needs to follow aseptic sampling technique.
The person(s) taking the samples should also be trained to sample surfaces/conditions that may appear different than they usually do. For example, when an area is wet where it is typically dry.
Swabbing should be performed at a minimum 4 hours after the start of production to allow targeted pathogen or indicator that may be harboring in niches to spread out to the equipment and area where they can be detected.
Day of the week and time of the day should be rotated. For daily operation, time of the days should be rotated between the different shifts. For weekly operation, day and time of the day should also be rotated so sampling does not always happen on Mondays and Tuesdays, but also later in the week and on weekends. The intent is to verify that controls in place are effective on all shifts/days of production.
Sampling Results and Trending
Once results are available, they need to be communicated in a timely manner and actions taken as soon as practically possible. In most cases for equipment cleaned daily, the investigation and corrective actions can begin within 24-48 hours after the results are available. For equipment cleaned weekly, or less frequently, the investigation should begin within 24-48 hours after results are communicated and the site team has to determine if production should be stopped for actions to be taken or if production can continue while actions are taken.
Action(s) taken should be verified by re-sampling the positive location until three consecutive negative results. We recommend to spread the re-sampling over 3 weeks, unless one of the re-samples is positive (repeat positive), to provide a better perspective on the sustainability of the action(s) taken.
Many facilities are now accustomed to escalating their actions after a repeat positive. Tracking and trending positives over time (about 3 years) on a map can provide insightful information on potential sources of sporadic findings. For example, if a number of positives are found at the floor level (drain, floor, employee boots, lower part of equipment, etc.), it may indicate that there is a niche is the area which has not been detected and eliminated, or one the barrier is not as effective as it could be.
Author: Commercial Food Sanitation, Richard Brouillette.