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By Lisa Lupo

The E. coli outbreak began in December 2017 stretching from Canada into the United States. The Public Health Agency of Canada eventually linked the outbreak to Romaine lettuce. But even while FDA acknowledged that its whole genome sequencing testing showed the U.S. and Canadian E. coli O157:H7 strains to be closely related, suggesting a common source of illness, the U.S. agency never did confirm a definite source. Nor did even this pronouncement come until well after the outbreak began.

Additionally, while CDC stated that the likely source of the outbreak appeared to be leafy greens, it provided no consumer advisory notices, specifically stating, “CDC is not recommending that U.S. residents avoid any particular food given the short shelf life of leafy greens and because a specific type of leafy greens has not been identified.”

The lack of information frustrated the produce industry which was being impacted by consumer wariness, as well as professionals across the food industry wanting to understand the issue to take precautions against putting contaminated product on the market.

It’s not the only time that a definite source of contaminated product has been unable to be found or that it has taken an inordinate amount of time to be determined. So, what can food processors do to detect and prevent pathogens in ingredients or processed product before it reaches the consumer? Following are 10 steps for prevention and 10 steps for detection to protect your products and consumers from pathogens.


1. Build a strong food safety culture. A key element in building a culture that takes food safety seriously is proper workforce education and training, said 3M Food Safety Global Scientific Marketing Manager John David. Increasing staff awareness of how food safety issues can arise and ensuring that proper behaviors are being taught and reinforced by company leadership are important steps in ensuring that a facility is consistently producing safe food.

2. Prevent produce contamination through Good Agricultural Practices, including cultivation and irrigation practices and workforce hygiene, said Hygiena Chief Scientific Officer Martin Easter. Fecal runoff in water and irrigation systems can contaminate crops and pickers have been known to cause cross contamination.

3. Implement Good Manufacturing Practices (GMPs) for post-harvest transportation, storage, and handling prior to processing, Easter added. This includes raw material control and supplier quality assurance programs; critical control points to reduce or eliminate hazards; segregation of raw and cooked foods; high hygiene standards; restriction of environmental cross-contamination on air, people, equipment, raw materials, pests, water; and finished product testing.

4. Ensure your pre-requisite programs solidly address, but go beyond, typical program requirements that are aimed at reducing or eliminating pathogen cross contamination. Such programs should include proper hygienic zoning, sanitation procedures, sanitary equipment design, sanitary plant design, and preventive maintenance. Also, David said, facilities should implement best-in-class programs that include the concepts of the Food Safety Modernization Act (FSMA) preventive controls principles, such as developing effective ways to conduct monitoring, verification, and corrective action; and maintain appropriate records.

5. Have a full understanding of the step-by-step processes of your products, from the moment the ingredients arrive to the moment the finished product leaves the facility to reduce the opportunities for cross-contamination to occur.

6. Review and implement monitoring plans at every step of the product life-cycle, from sourcing and receiving raw material and ingredients through production and packaging of the semi-finished and finished product, David said. Ensure you are aware of and control all high-risk movement of the product and people.

7. Implement a comprehensive environmental monitoring program as an essential component of your food safety system. “This provides a critical tool to verify that your facility is in microbiological control. For facilities subject to FSMA’s Preventive Controls rule, it verifies that these are working as intended,” David said

8. If you produce ready-to-eat foods that are exposed to the processing environment, proper implementation and execution of environmental monitoring programs can provide numerous benefits. In addition to preventing product contamination and potential safety recalls by identifying sources of pathogens in the environment and eliminating these hazards, these programs can help to extend product shelf life, improve food quality, and optimize production processes.

9. Include robust root cause analysis and continuous improvement strategies in your environmental monitoring programs. If your environmental monitoring detects a positive, don’t just immediately clean and sanitize the area, then retest to obtain the necessary negative (or clean) result to continue processing, David explained. Instead, take that one step further and determine the underlying cause of the problem, such as enhanced vector swabbing and testing, rather than just controlling a specific outgrowth of it. This is just one example that can provide greater understanding into the root source of the issue.

10. Take a proactive approach and employ strategies to reduce the presence and persistence of pathogens in your environment. By using and documenting a “seek and destroy” program, you can start to predict where, when, and why problems occur. Long-term improvements will have significant benefits — not only on food safety and food quality, but on the efficiency of the production process.

Have pathogen detection equipment that is top of the line, but easy to use and calibrate.


1. Bring the Internet of Things (IoT) into the world of food safety. Whether connecting your diagnostics to your supply chain or having software that enables you to trace each touch point, IoT allows the physical elements and pathogen detection to connect with the software that facilitates the movement of goods to consumers in a safe, traceable, and effective manner, said Pathsensors Food Safety Consultant Lead Donald Grim.

2. Test all raw material and finished product for hazards, indicator organisms, and pathogens, Easter said. This should involve the monitoring of process control parameters; time, temperature, and/or residual hazards; or indicators such as ALP in dairy products, he explained.

3. Identify high-risk raw materials and ingredients and ensure that test methods and protocols validated for these food matrices are used and capable of detecting pathogenic hazards. For example, David said, foods such as spices, cocoa powder, and vitamin blends can have a negative impact on the recovery or detection of the microorganisms, so it is critical to ensure tests are validated for the specific food matrix being tested.

4. Continuously conduct environmental testing to find and eliminate the cause of pathogen contamination before it impacts product or consumer health. Assurance of food safety cannot be accomplished solely through end product testing.

5. Finished product testing should not be the only method used to test for pathogens, but it does need to be incorporated as verification of your food safety system. Employ a risk-based sampling and testing program that’s tailored to the food you produce, the facility, and the nature of process controls employed, David explained.

6. Maintain high hygiene standards to include monitoring of surfaces and rinses for residual products, indicator organisms, and pathogens.

7. Implement methods to monitor for indicator organisms and pathogens, such as total aerobic bacteria, coliform, E. coli, Enterobacteriaceae, or spoilage organisms like yeasts. Specific pathogen tests will determine the existence of target species and strains like STEC, Salmonella, or Listeria monocytogenes, Easter said.

8. Use rapid pathogen testing methods in your test-and-hold process to overcome the challenges of limited product shelf-life, particularly produce, which allow very little time for pathogen testing. Rapid detection enables production and distribution decisions to be made with speed and certainty; prevents food waste; and ensures pathogen-free food is moving onto customers.

9. Have pathogen detection equipment that is top of the line, but easy for everyone to use and calibrate, Grim said. If only the food safety team is able to use the technology, it can’t do its job when they aren’t present. So, everyone — from those working on the processing floor every day to the office managers — should know how to use the equipment easily, quickly, and accurately, he explained. Ease of use is particularly important because those who perform the tests multiple times every day may come from a variety of backgrounds and education levels.

10. Require certificate analysis from your suppliers, Grim added. This certificate guarantees that your produce suppliers are testing for pathogens, so a certificate should be provided with each load to help you identify and isolate any contamination problems.

The author is Editor of QA magazine. She can be reached at llupo@gie.net.