Keeping it Biosafe

In late April, the Centers for Disease Control (CDC) issued an investigation announcement on a multi-state outbreak of Salmonella typhimurium infections associated with exposure to microbiology laboratories. Many of those who became ill reported having worked with Salmonella bacteria in the lab or lived in a household with someone who did.

Although such outbreaks are not frequent occurrences, accidental contamination from pathogenic lab sampling and testing is always a possibility, and is a critical reason for both in-house and third-party labs to create and follow biosafety plans specific to their operations.

A lab’s biosafety plan should include handling of samples, lab access, and employee training and safety procedures, based on the CDC guidance document, Biosafety in Microbiological and Biomedical Laboratories (BMBL).

The guidelines focus on the Biosafety Levels (BSL) of the tests a lab performs. Biosafety Levels range from BSL1 to BSL4, with most testing conducted on foods falling within BSL1 (such as non-pathogenic quality tests) or BSL2 (such as those for E. coli, Listeria and Salmonella), with biosecurity tests often at BSL3 (such as that for Bacillus anthracis). “The higher level you are, the more restrictive the regulations will be,” said Michelson Laboratories Microbiology Manager Wendy Lu.

The Biosafety Plan. In developing a plan, said Melinda Hayman, principal scientist for Food Safety Net Services, a lab should consider security aspects, such as who will have access to the lab, how they will be trained, and procedures for entering and exiting.

Limiting access is critical because non-laboratory workers often don’t know the necessary safety procedures, said Brad Stawick, president of Stawick Laboratory Management. “They don’t know what they might be touching or what they might be interfering with.”

“Only people who need to be working in the lab should be there,” Hayman agreed. And within the lab, workers should not be moving between the pathogenic and non-pathogenic areas. Controlling access through the use of key cards is one good biosafety option, particularly in areas where cultures are stored, she said.

Segregation of samples is critical to biosafety in the lab. For example, if a lab conducts both BSL1 and 2, Hayman said, “You should have the lab set up to segregate samples of those which may have pathogens and those which do not.”

In addition, the lab should have a separate air handling system to keep from inadvertent contamination of the processing area. “Negative pressure is usually required for a Biosafety Level 3 lab so that pathogen does not flow outside of the lab,” Lu said. Even as an external lab not associated with a food plant, “we have different filter systems, so air going into the pathogenic lab is very clean,” she said. “We want to prevent cross contamination from in the lab to out, and to maintain clean air [within the pathogenic area] so we don’t contaminate the samples either.”

In-House OR Third Party. An option that a plant could consider to help control its biosafety risk, and limit lab investment, is to conduct quality and BSL1 tests internally, but outsource BSL2 and above testing to an external, third-party lab. This can be helpful not only to avoid cross-contamination, but to ensure the highest level of expertise without having to invest in testing, annual recertification, and biosafety equipment, such as biosafety cabinets which are recommended for any pathogen testing, particularly for aerosols and agitation tests. “It is an extra barrier between yourself and the bug, and the environment and the bug,” Hayman said.

Stawick has seen seesawing trends in food processors maintaining in-house vs. outsourcing pathogenic testing. “There almost seems to be a cycle in the industry,” he said. Companies start outsourcing, then decide it would be less expensive to do it in-house; so they switch, then after a while decide it would be less expensive to outsource. “It’s one of those ongoing things.”

Those who use third-party labs often do so to minimize their risk. “They don’t want to risk bringing pathogens into the lab that could spread to the food area,” Lu said, adding that the costs of biosafety equipment can also be prohibitive. “Is it worth investing to establish a biosafety lab like that; or is it better to send it to a certified and accredited lab?” she asked.

When a plant does conduct its own, Stawick said, ideally the pathogen tests would be conducted in a separate building to protect against cross contamination of food products. When that is not possible or practical, he said, “you want as much separation from the plant floor as you can get,” including a separate entrance.

“You don’t want the plant floor to have direct access to the lab,” Stawick said, explaining, “You want to go through all exit procedures from the floor, then go through entrance procedures to the lab.” Otherwise there is a risk that contamination could be tracked between the areas.

Entrance and exit procedures should also include hand- and foot-care. “It is a regulation that you have to wear gloves when working in a pathogen room, and change when entering or exiting,” Lu added. “You must also wash your hands when going in or out of the lab or use sanitizer.”

Because contamination can also be tracked by foot, a variety of protections are used for prevention, including foot baths, dry sticky-trap mats, and separate lab and plant shoes.

Training and Education. In addition to initial training, continuing education is important in lab situations as consequences can be dire. Without continual reminders, workers can become complacent, and forget how serious it is, Hayman said.

“Everyone working in the lab—whether washing glassware or advanced level—are both equally at risk, so you need to be sure that both understand there is a risk and what the risk is,” Stawick affirmed. In addition, he said, “The safety training needs to be very focused on what is expected of employees and what they may come in contact with.” For example, he said, a person may just be doing indicator tests, but is next to pathogen testing, so he or she needs to be aware of what is happening all around.

Although technological advances in testing are good for food safety, the ease of today’s testing could also lead to laxness. “As testing has gotten to be more and more black box,” Stawick said, “I wonder if it’s become so routine that people don’t think about ‘I have a gallon of Salmonella here.’ I don’t know the answer to that.”

The author is Managing Editor of QA magazine. She can be reached at llupo@giemedia.com.