The Sample Has Been Taken, the Results Are In: Now What?
By Margaret D. Hardin, Ph.D.
We spend a considerable amount of our time in the food industry collecting data. Data may be quantitative or qualitative, and may be the result of one or more of numerous methodologies from an air settling plate or a swab to the analysis of a sample using high-performance liquid chromatography for the presence/absence of a chemical of concern. Data could also be from microbial mapping using molecular methods such as genetic fingerprinting. Data are generally the results of measurements, either objective or subjective, which are designed to evaluate the subject matter in a multitude of ways: sensory, physical, chemical, microbiological or particulate. Such information may be obtained to develop and/or verify raw product specifications (ingredients, supplies, water or air) as well as track suppliers, monitor employee hygiene and/or the processing environment to verify sanitation, develop and verify product shelf life, validate products and processes, or verify finished product food safety and quality specifications. You have gone to all the trouble and expense to develop objectives, outline the plan, decide where and how to take the sample, evaluate the best available, cost-effective method to employ to test the sample, chosen a laboratory to analyze the sample and then waited for the results, oftentimes with a truck at the loading dock or a vice president on the phone. The results are in, and the worst thing you can do now is to put those results away in a drawer or store them away on the hard drive. The best thing you can do is to put the data to work for you.
Hopefully, you thought ahead and made wise decisions before you even took the sample so that the results would be meaningful and useful. Now it is time to get down to the business of analyzing, tracking and trending your data. While many factors are involved in food production and process control, having an objective measure will help you manage improvements to determine whether something is getting better or worse. Proactive tracking and trending of data can facilitate a root-cause analysis to discover and understand the originating causes of problems, to track the potential source of contamination to avoid delays in product release or to complete investigations, and to identify areas that can benefit from further investigation or process control. Using your data to lead you through activities, such as performing a root-cause analysis, is much more effective than using the “apply a band-aid” approach to fix issues. Trending of data is important to demonstrate a state of control to identify problems before they get too big (set alert/alarm/threshold limits), to identify process improvements and to determine whether improvements are effective. Trending of microbiological test results, for instance, can make it easier to spot patterns in your data and better manage the risks associated with your process and products. You can also trend your data to manage deviations in quality, Good Manufacturing Practices (GMPs) and regulatory compliance. To raise your overall level of awareness of what’s working well and what areas need to improve, use your data to objectively “tell it like it is.” The right numbers can provide invaluable insight to help focus your energy and resources on what drives results and give you the opportunity to strengthen the areas that need it most to reach your food safety and quality goals.
How to Use Data
For example, most processors of ready-to-eat (RTE) foods have developed some sort of program to monitor their post-lethality/finished product environment for microorganisms of concern and/or associated indicators. These results can then be used to track and trend any adverse conditions to demonstrate that the environment is under control. Results should be tracked and trended on a predetermined frequency, such as daily, by the quality assurance (QA) or food safety manager and reviewed regularly (e.g., weekly) by the facility food safety team to identify potential routes of transmission or harborage areas. Some companies use regularly scheduled production meetings to present data such as deviations in food safety best practices, environmental sampling, GMPs and quality. The meetings generally include those persons who drive food safety from the top, such as the plant manager, or who can make recommendations for and/or implement corrective actions (production supervisors, maintenance, human resources, etc.). Identifying and communicating these trends proactively will allow corrective actions to be implemented before a situation develops where there is a loss of control.
Trending. Recommended methods of trend analysis include examining each set of test results for unusual patterns and may or may not include the use of statistical process control (SPC) programs and control charts. Sample results should be examined on a daily, weekly or monthly basis, depending on your sampling frequency, for unusual patterns and sources of variation. The results can be tallied quarterly and include the current quarter and the previous three quarters to look for trends on an annual basis. This also allows the facility to note any trends that may occur seasonally. The results can be sorted between facilities manufacturing like product, across an entire facility, by process area, by production line and/or by time, shift, zone, site and/or surface type (e.g., drains). The analysis can be applied to include totals by month or quarter and ranking within a sort category—for example, by “hottest” or highest risk drain(s) among all drains—to ascertain any correlations with seasons or episodic events. To facilitate trending of results, ensure that samples are documented as preoperational/operational/postoperational and by time and location (site). Mapping out positive and negative findings on a plant diagram can be very useful. Different colors can be used to show positive and negative results, and positive results can include the date and shift the sample was taken as well as any corrective actions taken. This can be extremely valuable in visualizing trends and issues.
Monitoring. As previously mentioned, SPC and control charts can be applied to monitor and control the process and are often used to visualize and detect trends to see whether your process is in or out of control. They can be used to monitor production to detect risk of exceeding control limits, evaluate performance of suppliers, provide a warning of potential pathogen event or narrow down sources of a problem, that is, employee vs. process-induced failures. As the saying goes, “a picture is worth a thousand words,” and some people respond better to a visualization of data, which a control chart can provide, than to tables or spreadsheets of results and data points. There are many different types of control charts and as many different types of SPC programs. They can be used to demonstrate that a process is currently under control, they can show improvement following the implementation of corrective actions and, in some cases, they can also be used to predict future performance. In addition, SPC analysis and control charts can help determine the sources of variation in a process or nonconforming product. For example, X-bar charts can be used to see whether any results are above or below a desired baseline, whereas Pareto charts are used more in determining defects based on attributing factors. Be sure to pick the method of analysis that best applies to your particular dataset and meets the needs of your process and control parameters and goals.
From Data Analysis to Corrective Actions
The results are in and have been tracked and trended. Now the real work begins, as you outline and implement corrective actions and perform any necessary root-cause analyses. Corrective actions and preventive measures should be selected by the team, based on history and experience, as most effective for the exact situation that has been identified, and may include elements unique to that situation. It is often useful in these circumstances to develop an action plan assigning responsibilities to the appropriate members of the food safety or production team. This should not be a one-person QA responsibility, no matter how large or small a company might be.
Going back to the environmental monitoring program example, corrective actions in this case may be outlined differently, depending on where a positive result was found, such as in a drain or particular sanitary zone (1–4). There may be certain immediate corrective actions such as immediate cleaning and sanitation activities and/or the development of a Standard Operating Procedure (SOP) for applying a powdered antimicrobial floor treatment or gel to drains at start-up, breaks, shift changes, etc. and a longer-term remedy, such as replacing a drain, which may require an additional capital expense. Corrective actions should also include steps to verify that the organism of concern (e.g., Salmonella, Listeria and/or an indicator organism) has been eliminated from the area in question. The team may perform a root-cause analysis to assist in finding and preventing the source of the contamination. For instance, a root-cause analysis may begin with a simple review of the cleaning procedures for the entire area by the QA/quality control supervisor, sanitation supervisor and, if appropriate, plant manager. Any deficiencies in cleaning procedures will be corrected and additional training conducted as needed. The review team should evaluate whether a pattern exists. If so, the team will decide a proper course of action, which can include, but is not limited to, collection of diagnostic swabs to determine the root cause of the problem. These swabs can be used to identify potential harborage locations using a “seek and destroy” approach. In addition, and in the event of a positive result, the response team may also conduct an in-depth investigation, looking at areas and considering issues such as any maintenance disruptions/activities, facility construction and unplanned down time.
The investigation may also encompass other nonstandard production activities such as:
• An R&D plant trial
• An intensive review of equipment for harborage areas, such as hollow rollers, rough welds, cracked or damaged surfaces
• Extensive disassembly of equipment for thorough cleaning
• An audit of the sanitation process to ensure adequacy
• Intensified and extensive deep cleaning and sanitizing of the room and peripheral areas, including freezers, holding coolers and employee welfare areas
The team may also audit and conduct GMP refresher classes with all employees, including maintenance as needed, and look at replacement or heat-sanitizing of equipment. The response team should look at these factors and all relevant records and documents from the last full microbiological cleanup/sanitization prior to the current positive finding.
The success of the implementation and completion of a corrective action plan must be verified through follow-up, which may include additional testing. This may require resampling of a previously positive site and surrounding areas. If the site or sites that were positive are not in operation on the next day that the line will operate, the sampling should be completed when the site or sites of the original positives are in operation. If the original positive site is replaced with a similar piece of equipment, the replacement piece will be sampled. For example, if a table is positive and replaced with another table, the replacement table will be sampled. The team should perform a root-cause analysis to assist in finding persistent sources of contamination, such as the following: multiple positive findings at a single location, multiple positive findings at locations near each other and multiple positive findings at locations that are of a common type (e.g., wheels or floors).
Get Your Data on Record
Last but not least, there must be proper documentation of the events from the data through the corrective actions, root-cause analysis and verification that the corrective action(s) was effective. Document a timeline, including the date and nature of the deviation, the action plan, the investigation, the results of the investigation, the corrective actions applied, results of any resampling, training records, new SOPs developed or changed, new equipment or construction and conclusions. This is your chance to tell the story and document it for evidence of process control and for future reference. Unfortunately, the precise root cause is not always easy to determine nor is the precise origin of the deviation always that clear-cut. In fact, there may be multiple sources. In addition, and in an effort to get production up and running again, many changes may be made to the process at one time, making it difficult to pinpoint the exact source of the deviation.
Using your data to work for you through tracking and trending guarantees a favorable outcome for everyone involved—particularly the consumer. And, when used, in the case of environmental monitoring and process control of RTE foods, in conjunction with an aggressive and intensive sampling and testing program, it enables the facility to find and eliminate the root cause and verify the sanitary conditions of the production environment, going a long way toward identifying and minimizing the potential for microbial contamination of product through monitoring and management of suppliers and of the RTE process and production environment.
Margaret D. Hardin, Ph.D., is vice president of technical services at IEH Laboratories & Consulting Group. Previously, Margaret held positions as associate professor in food microbiology at Texas A&M University, director of food safety and quality assurance with Boar’s Head Brand, director of food safety at Smithfield Packing Co., Sara Lee Foods and the National Pork Producers Council and as a research scientist and Hazard Analysis and Critical Control Points (HACCP) instructor with the National Food Processors Association in Washington, DC. She currently works closely with the food industry in food safety and food microbiology-related areas, such as process control, process validation, environmental testing, HACCP, shelf life, training, sanitation and sanitary design. She is a member of the Editorial Advisory Board of Food Safety Magazine.