Sanitation Activities after Receiving an Out-of-Specification Microbiological Result

Editors’ note: This is part 2 of a three-part series on environmental monitoring. Part 1, which explored the first steps in implementing a cleaning/sanitation process, was published in the August/September 2020 issue of FQ&S, and part 3, which will cover procedures for use during extenuating circumstances, will publish in the February/March 2021 issue.

In Part 1 of this three-part series, we discussed the basics of sanitation, soil, and chemical identification, in addition to basic procedures and applications for routine cleaning and sanitation. In this article, we will discuss root cause analysis and intensified cleaning and sanitation activities to perform after receiving an out-of-specification (OOS) microbiological result during routine environmental monitoring.

Let’s begin by stating that OOS results are an expected, albeit perhaps not welcome, outcome of a robust microbiological environmental monitoring program (EMP). Usually, we find that cleaning and sanitation procedures are a common scapegoat, if you will, for an OOS. While this may be part of the story, we have found that OOS results signify that the EMP is working as intended, meaning that the results will detect whether there is a gap or drift between procedures as they are written versus what is occurring on the plant floor; if the written procedures do not address circumstances that lead to cross-contamination; or if there is a situation festering that, if not addressed, could lead to a major production disturbance. Taken together, OOS results are a shot over the bow and encourage bridging the food safety and sanitation departments in performing augmented procedures.

So, what do we mean when we say augmented? Let’s start by giving an example. A company is enjoying an increase in sales and the plant is producing 30% more product, which undergoes a thermal lethality step. To meet the production demands, the second shift is running late and encroaching into nightly sanitation time. Months into this schedule, trending of the coliform counts shows the quality team increasing counts on equipment during the second shift. Two weeks later the increased counts are then noted during first shift and then at pre-op, where <10 cfu/sponge is the specification. Microbial analysis on retained product identifies swelling packages before the end of shelf life, and coliform counts are well above specification.

The quality manager takes five 360° vector sponges surrounding each of the equipment sites with OOS coliform counts and identifies three pieces of equipment where the vector sponge counts are high. The HACCP team determines that, on the next down day, maintenance will disassemble the equipment to the frame. During disassembly, sponges are taken, and there are copious amounts of accumulated product residue tucked deep inside numerous crevices, all with a rank odor. Sanitation performs an intensified cleaning of the area. After sanitation, verification samples are taken and sanitation is determined to be effective. The equipment is then reassembled by maintenance and the equipment sanitized again.

While waiting for results, the sanitation records are reviewed. Records indicated that due to second shift time overruns, the sanitation team does not disassemble the equipment or sanitize all equipment in order to save time. As preventive actions, the sanitation manager shift is changed to overlap with production so she can verbally report activities or issues to the HACCP team in morning meetings. Further, checklists are devised to capture each step in the sanitation standard operating procedures (SSOP), including equipment disassembly, chemical concentrations, and applications on each piece of equipment. Additional sanitation personnel are hired to allow for SSOP adherence.

Let’s unpack this scenario. What went right?

1. We’ll assume that a risk assessment identified coliforms as a risk for product spoilage.
2. Organisms identified in the risk assessment were added to the EMP, which, as one of its purposes, is a tool to identify gaps in sanitation (or other food safety) programs.

• Suggestion: Sampling frequency, timing (first, second, or pre-op shift), sampling sites, zones, and organism selection should be predetermined and based on risk assessment of the facility and product.

3. EMP specifications were set and samples were taken during pre-op, first, and second shift of operations.

• Suggestion: Specifications are based on collection of baseline data, which are accumulated over an extended period (i.e., at least six months to account for seasonality) and trended to understand the normal concentrations of microorganisms in that specific manufacturing facility and during each shift (accounting for building age, equipment condition, products, number of employees). After specifications are set, exceeding their limits results in investigation and corrective actions.

4. The results were trended and noted to increase.
5. Retains were saved and tested for the organism found to be OOS.
6. Vector samples were taken to assess origination and scope of OOS results.

• Suggestion: Root-cause analysis should include additional sampling to determine the location of the source, or harborage site, which is often different from the sample site. This is called vector sampling, which includes sampling beyond the OOS point to other locations in the vicinity. Vector samples are those taken in a 360° radius, up to 30 feet from the original OOS site, including the ceiling, walls, and floors. Water droplets from cleaning, air currents, cross-contamination from tools, hoses, utensils, and people are all means of translocation from a harborage site to external locations. Harborage sites are those locations that are difficult to inspect, reach, or clean. In this regard, they are usually not product contact areas (Zone 1); rather, they are areas further removed (Zone 3). They usually have access to water and a food source, typically product build-up. Harborages can allow bacteria to accumulate, grow, and then excrete back out into the environment. Harborages can be present for weeks, months, or even years. Eventually, the bacterial concentrations will build to a point high enough that they will be detected on nearby equipment or product.

7. The HACCP team met to discuss the EMP results and determine next steps.
8. Maintenance disassembled the equipment to the frame and, before any cleaning of the equipment, coliform samples were taken and a visual inspection conducted.
9. Sanitation was present during the disassembly process and conducted an intensified sanitation procedure. They were able to witness where in the equipment the soils were accumulating. An intensified cleaning procedure (deep clean) includes a number of steps that are expanded from routine cleaning. These include:

• Equipment disassembly: Do this to the framework or as close as possible.
• Manual scrubbing: Although this is the hardest method to control and monitor, this may be the most effective way to clean in areas that are difficult to access. Two rounds of detergent application, which involves the use of alternative chemicals (i.e., apply chlorinated alkaline first, rinse, then apply alkaline) or the same cleaning chemicals but in higher concentrations than used in the routine process, should be conducted. These stronger chemistries should be used with caution and only on an intermittent basis due to potential damage to the equipment or environment and strict enforcement of personal protection equipment. Consultation with a chemical supplier is suggested prior to conducting any type of change. The best practice for small parts removed during disassembly is using two buckets: one bucket with detergent and one with sanitizing solution. Small parts may then be left in the sanitizing solution until retrieval for reassembly. Use non-scouring pads, single time only.
• Sanitizer application: After rinsing detergent, apply an environmental strength (the high end of a chemical supplier’s recommended parts-per million) sanitizer. Rinse and apply a second round of sanitizer, which may be a different compound than the first. Rinse food contact surfaces. At this juncture, swab equipment, assemble, and apply a third round of sanitizer (food contact concentrations for Zone 1 and 2 and environmental concentrations for Zone 3). Although sanitizers are effective across a broad spectrum of microorganisms and have proven efficacy per EPA standards, certain sanitizers have greater efficacy against specific types of organisms than others. For example, chlorine dioxide is extremely effective against Gram-negative and Gram-positive bacteria, but weak against yeasts. A facility applying chlorine dioxide may experience yeast contamination in the environment, meriting a switch to peroxyacetic acid, which has efficacy against yeasts. Chemical substitution should not be implemented without a risk assessment and a discussion with a chemical provider.

10. After sanitation, verification sponges were taken to verify that the sanitation procedures were effective. There are times when the harborage is longstanding. One intensive cleaning and sanitation event may not be effective and another is needed. After maintenance reassembled the equipment, it was sanitized again to avoid contamination during assembly process.
11. Preventive actions were identified and implemented. Cleaning records provide an additional awareness of breaches in protocol. For example, insufficient concentrations of cleaning compounds lead to product build-up and potential biofilm formation. Records give indication of trends in microbiological creep data. If equipment is not being cleaned according to the SSOP, bacteria counts tend to increase over time. Equipment that may not have been fully disassembled in the past will now be put on a disassembly schedule and dismantled to the framework (or as close to this state as possible). By removing parts, hollow areas and or damages are exposed that would otherwise be impossible to reach, see, or sample. During disassembly, use a designated mat with specific top and bottom identified or a dedicated rack to contain parts. Do not place parts directly onto the floor. Always clean mats after use and hang up in a designated location to allow drying.

While a one-size EMP or cleaning and sanitation regimen does not fit all, there are baseline tasks that can be incorporated into all programs to set up your integrated food safety program for success, regardless of changes that will inevitably occur. Incorporating predetermined steps into an EMP program when there are OOS results, and using the strength of the entire HACCP team will aid in a successful approach for bacterial management.