Welcome to FOOD SAFETY FEUD...Listeria Edition

Where the points don’t matter, but your swab sites for Listeria definitely do! Today’s question on the board: What are the top reasons food companies struggle with their environmental monitoring programs (EMPs)?

All joking aside, we write this blog with the knowledge that often, FSQA managers haven’t seen very many environmental monitoring programs. Maybe they’ve worked in another facility or two, or maybe they only know the plan their predecessor developed. But we’ve seen a lot – enough to look across the board and see very common themes emerge in our work with clients. For those who haven’t had the benefit of working with or seeing lots of EMP programs, particularly when Listeria is the target organism, here are our top observations. Before diving into the list below, take 5 minutes and jot down YOUR operation’s challenges and see where you land on the board!Now let’s dive in…Survey says…DING!

Number 1: Swabbing only after sanitation

Turns out, if you only swab after sanitation, and not during operations/production, you’re missing a big opportunity to catch the Listeria that might shake loose from the equipment. 

Number 2: Avoiding Zone 1 like it’s radioactive

People love to swab drains, floors, forklifts (and for good reasons), but…Zone 1 – X Even during vector swabbing? XX And if they do the swab and get a positive, cue the panic, the emergency meetings, the unwarranted calls to buyers, someone whispering “burn the plant down!”….XXX

Let’s move beyond this trend. The policy and guidance on Listeria clearly discusses the value of moving to Zone 1 in an effort to create an aggressive and thorough EMP program. Just be sure to know how to handle a Zone 1 positive before you venture down this path (Note: the resource linked is produce specific, but many of the same concepts apply across commodities/food products). 

Number 3: Swabbers with no flexibility

And no, we don’t mean being able to do a split or complex gymnastic move to get at a swabbing site (though this skill can be useful for hard-to-reach areas!). If a swabber sees something concerning but is instructed not to swab because “it’s not on the list,” you’ve created a scavenger hunt rather than a robust program which explores all possible sources of contamination. 

Number 4: The Swab Square of Doom

Yes, it’s tidy. Yes, it’s measurable. But prescribing a 12x12” or 4x4” area without recognizing that this forces swabbing on a flat square surface ends up missing the nooks and crannies and that weird underside of the conveyor belt bracket that no one wants to touch – that’s where Listeria may hide. 

Number 5: Ignoring FDA’s Table 6 for Corrective Actions

Table 6 exists for a reason (See Page 50). But it is amazing that many EMP programs don’t have a clearly outlined process for escalating a positive. Even when companies do follow it, they often clean before re-swabbing — which, you guessed it, sends us right back to point 1 on this list. 

Number 6: Sanitizer application alone  ≠ Harborage remediation

(This one gets a collective groan from the audience)Spraying sanitizer on a harborage site is like spraying perfume on a skunk. It smells better for a minute, but the problem is still very much alive. If you have a known or plausible harborage site, devote your full attention to the issue. This might mean full scale cleaning and sanitation efforts, disassembly of equipment, and/or replacement of equipment/components causing the problem.

Number 7: Sanitizing before conducting vector swabs

If you sanitize before vector swabbing, you’re not doing environmental monitoring — you’re doing evidence destruction. In a root cause analysis, this is your opportunity to shine! 

Number 8: Documents Strewn Across 10 Folders with No Trending

Environmental monitoring is a trend-based program. But some companies keep every result (which could be hundreds or thousands!) as a separate PDF in a folder named something like “Swabs 2025–Present FINAL.” You can’t trend what you can’t see. You’re devoting valuable company time and money to do the swabbing, USE THE DATA. Don’t let it sit in a folder containing 50 separate PDF files to rot.

Number 9: Setting KPIs for Positives

A KPI like “no more than 5% positives” sounds good until you realize it incentivizes people to…not find positives. Which is the opposite of the point. Environmental monitoring is not golf - low scores aren’t always good.

Number 10: When Your Zone 3 Positive Could Actually be a Zone 1

Zone 2, 3, or 4 positives - nothing to create too much alarm over, right? Not so fast… Let’s consider a situation where an employee has touched a Z 2/3 button, lever, or part of the equipment and that location is positive for Listeria. Where else in the facility has that employee moved and potentially cross-contaminated? Did they return back to the food line without appropriately cleaning and sanitizing their hands? Z1 broadens substantially when you begin to think about it more in the framework of “Can product be contaminated from this?” rather than “Did the food directly touch the Z1 surface?” 

Final Round: Fast Money

We asked 100 top food safety professionals – “what’s the REAL goal of an environmental monitoring program?” 

Top answer: To find Listeria, not avoid it, and to get it out of where it lives, not just temporarily kick it out (otherwise, it will come back!). Second answer: To understand your production environment well enough to control and mitigate the risks. Third answer: To use the data to drive risk-based decision making. 

Ok, we didn’t actually survey 100 of you…but that’s what we think many will say! Let us know in the comments what would be on your Listeria list!