During a 60-day period between mid-March to mid-May, the FDA issued six product recalls due to Listeria monocytogenes, the bacterium that causes Listeriosis. Listeriosis is a serious infection with symptoms including convulsions, loss of balance and fever in healthy adults as well as miscarriages and stillbirths amongst pregnant women.
In this same 60-day period, there were also:
- 13 product recalls due to Salmonella
- 3 product recalls for bacterial contamination
- 6 product recalls for the “presence of visible particulates”
Fortunately, for all the instances in this 60-day period where the bacterium Listeria monocytogenes has been identified, no known illnesses have been reported.
Rapid growth of bacteria
According to the Centers for Disease Control and Prevention (CDC), each year approximately 1,600 people in the United States get sick from Listeriosis, as well as an additional 1.2 million illnesses caused by Salmonella, which results in approximately 450 deaths.
Bacteria reproduces logarithmically; where one cell becomes two, which then divides into four, then eight, and so forth. If conditions are ideal, this doubling can occur every 15 minutes so that within five hours a single cell can become more than a million cells! Ideal conditions can be any area that is not properly sanitized and oxygen is present, such as cracks or crevices.
While the FDA is consistently working hard to protect the public from consuming suspect products, it is still the goal of the entire food and beverage industry to avoid the potential issue altogether.
How gaskets may promote bacteria growth
Thousands of gaskets are used daily throughout food and beverage processing plants at every hygienic union. They are inserted between two flanges and connected using a tri-clamp. The process for installing, maintaining, cleaning and removing these gaskets is a critical aspect of preventing bacteria growth.
Unfortunately, the design of the clamps is susceptible to human manipulation. Inconsistencies on how much a clamp is tightened results in either a recess or intrusion of the gasket, relative to the ferrule and ultimately the flow path. Figure 1, shows how intrusion disturbs product flow. If you can imagine that same flow to be the CIP solution, a pipe cleaning solution, it becomes clearly evident that the space beneath the intrusion is not being properly cleaned.
Typically, a gasket intrudes (on average 0.050 inches) into the flow path, which in turn increases the potential for cracking of the gasket material. This crack could potentially harbor bacterial growth or cause gasket material to break off into the finished product.
Ensuring consistent alignment in thousands of locations throughout a facility can make cleaning, sanitizing and properly draining a system far more difficult than if the interface were flush.
There is no doubt that food and beverage processors are very conscious about the safety of the products they produce. Utilizing highly trained personnel, they diligently and routinely sanitize their equipment, inside and outside, as well as their walls and floors. Yet, the issue of gasket contamination remains one area that is not completely understood. Any efforts that can be made to potentially make it easier to prevent this area of bacterial growth need to be considered.
One solution to this issue is Parker’s Integrated Sealing Systems Division (ISS) over-molded sanitary gasket. This gasket is engineered to consistently achieve intrusion levels of less than .008 inches. This mitigates the possibility of cracking, gasket debris in the product stream or harmful bacterium growing in crevices that the CIP failed to adequately reach, as shown in Figure 2.
For more information regarding Parker’s hygienic sanitary gasket, please visit the Integrated Sealing Systems Division.
This article contributed by Emanuel Guerreiro, Industrial Market Development Manager, Parker Hannifin Integrated Sealing Systems Division.