Using rapid microbiological testing effectively in meat and poultry processing
Microorganisms can be beneficial in certain sectors of the food industry, but by and large, they are not beneficial in meat and poultry processing facilities. Pathogenic bacteria and spoilage organisms can cause a host of problems, including foodborne illness in consumers, damage to the brand and economic loss due to recall or product destruction. Therefore, it is very important to monitor these facilities and test for microorganisms in an effort to reduce them in the meat and poultry processing environment.
Rapid microbiological testing is one tool that enables processors to detect and assess potential microbial contamination…well, rapidly. Speed-to-result is key when you’ve got a product hold-and-release program in play, want to ensure compliance with relevant government regulations, or need to validate and verify that your Hazard Analysis and Critical Control Point (HACCP) process control measures or sanitation methods are working to plan. In a meat or poultry operation, where typically there is no on-site microbiology lab, rapid methods can help screen problems proactively in certain key areas, including environmental monitoring and verification of process control efficacy.
Environmental monitoring
For most meat or poultry operations, rapid methods are commonly used to monitor the cleanliness of the processing equipment and environment. Sterile single-use swabs, pre-moistened sponges or sponges on a stick are used to take surface samples within the facility and can then be analyzed in the lab to determine bacterial counts and types of organisms that are present in the tested areas.
Test results should be trackable to each area tested and should be reviewed and recorded to know areas of concern, and also give the facility historical data if numbers of bacteria suddenly increase or if a sample tests positive for a pathogen. Several areas can be swabbed around the positive site and sent out for testing, which will helpful in tracking the source of the pathogen. Any positives found from that set of tests would have swabs taken around them and so on until the source can be determined and eliminated.
Cleaning and sanitation are important in all food processing facilities and a wide variety of cleaners and sanitizers are commercially available; many facilities use two different-acting sanitizers (i.e., acidic and alkaline) built into their cleaning schedules in an effort to reduce bacteria in the environment and on equipment and food-contact utensils. The use of adenosine triphospate (ATP) kits is an easy way to monitor sanitizer effectiveness.
ATP is found in all cells and therefore the results cannot be used to estimate bacterial load as food residue also contains ATP. This method measures how much ATP is left on the surface. The surfaces should be cleaned and sanitized as normal and allowed to dry, then an ATP swab is used to swab an area (preferably known size) and placed into the ATP monitoring luminometer device. In just minutes or less a numerical result is displayed which corresponds to the cleanliness of the surface tested.
There are many different manufacturers of luminometers and ATP swabs and many have technology built in to be able to download results directly to a computer for result preservation. They also have recommendations for acceptable and unacceptable number ranges for food processing facilities; for example, 10 RLU or less = pass, 11-30 RLU = caution, >30 RLU is fail.
Product testing
The other area in which rapid methods are used in the meat and poultry plant is end-product testing to determine presence/absence of pathogens. There are many different rapid spoilage and pathogen tests to choose from and you should consult your operation’s outside lab to decide what is important for your testing needs. More than one test may be performed on one sample, but you may need to send extra per sample based on the laboratory requirements.
Generally speaking, the faster the results, the more expensive the test. For example, 24-hour pathogen tests will cost more than conventional agar and broth tests, which can take several days. However, if you have trucks loaded and need to ship product more quickly, you may decide the extra cost is worth it.
Also, technology is available that can perform ‘genetic fingerprinting.’ This is useful because it can confirm sources of contamination by genetically comparing samples, which lets the facility know if a new organism has entered the plant or if it is a resident ‘house bug’ that has not yet been eliminated in the facility. An isolate is collected from an 18- to 24-hour incubated agar plate and then added to the machine with results available in eight hours.
Effective sampling
While end product testing is not normally performed on-site, taking samples aseptically and correctly to ship to your third-party lab is extremely important to ensure accurate results. Of course, this also applies to environmental samples.
When any food or environmental sampling is performed, care should be taken so that the samples do not become contaminated at the facility. Gloves and sterile sampling utensils must be used to ensure a true test of the sample. Sterile, individually packed sampling devices are widely available commercially and gloves should be changed between samples if they have touched the sample or become otherwise contaminated. Samples should be placed in sterile sample bags and clearly labeled. The labels can say whatever you wish as long as it easily references the location or sample for facility personnel and the lab technicians can easily read it for reporting.
Samples should be stored under refrigerated conditions until they can be analyzed or shipped to an outside lab for testing. If shipped, samples should be placed in a cooler box with a copy of the necessary paperwork, and frozen ice packs sufficient to keep samples cool until they arrive at the lab. Samples should be protected from direct contact with the frozen packs and package should be shipped using overnight delivery.
Be proactive
Proactive is always better than reactive when it comes to spoilage and pathogen control in meat and poultry processing plants. By focusing food safety plans on preventive interventions such as environmental monitoring, ATP testing, good record keeping, and knowing what and when to employ rapid pathogen and other microbial testing in your meat or poultry operation is key. Testing does not assure food safety but it can assure that you are continuously improving your process control capabilities. And importantly, it will reduce the need for crisis management, and ultimately, the risk to consumer health and costly food recalls.
— By Beth Ann Crozier-Dodson, PhD, president and food microbiologist, Crozier-Dodson Food Safety Consulting LLC