Navigating the Dry Zone: New Research Uncovers Critical Gaps in Low-Moisture Food Safety

In the high-stakes world of food manufacturing, "dry" does not always equate to "safe." While low-moisture foods (LMFs)—such as spices, bakery items, snack foods, and dairy powders—are inherently inhospitable to microbial proliferation due to their low water activity ($a_w leq 0.85$), they have become a notorious vector for persistent pathogens like Salmonella. A groundbreaking study from Cornell University has now shed light on a troubling reality: the very sanitation practices intended to keep these environments clean may, in fact, be inviting the biological hazards they are designed to eliminate.

The study, recently published as a pre-proof in the Journal of Food Protection, was spearheaded by Dr. Abigail Snyder, a leading dry sanitation expert and Associate Professor in the Department of Food Science at Cornell University. Alongside co-authors Grace Buechner and Dr. Calvin Slaughter, Dr. Snyder surveyed 40 industry professionals to map the current landscape of sanitation, moisture control, and microbial testing across the LMF sector. The findings suggest that the industry is grappling with significant inconsistencies in terminology, a pervasive lack of humidity control, and a dangerous reliance on wet-cleaning methods that conflict with modern food safety guidance.

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The Paradox of the Dry Environment

To understand the gravity of the Cornell study, one must first understand the unique challenge of LMF production. In a dry facility, water is the primary enemy. Pathogens like Salmonella can survive for years in a dormant state within dry particles or equipment crevices. When moisture is introduced—whether through a roof leak, condensation, or—ironically—aggressive cleaning—that dormant pathogen "wakes up."

"Environmental sanitation programs do not result in a sterile environment," Dr. Snyder noted in recent technical guidance. "Some microbial cells will persist after either wet or dry sanitation. Consequently, the introduction of water into the environment enhances the ability of those remaining microbes to grow."

The survey results highlight a fundamental disconnect between the intent of facility managers and the biological reality of their plants. While 95 percent of respondents reported using dry-cleaning methods like brushing or scraping at least weekly, a significant 22 percent of respondents admitted to performing "flood cleaning"—the liberal application of water to equipment and floors—at least once a month. This practice stands in stark contrast to the emerging scientific consensus that wet sanitation in a dry environment is a high-risk activity that often does more harm than good.

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Chronology of Safety: From Policy to Practice

The journey toward modernizing LMF safety has been a gradual, often reactive process. Historically, the food industry relied on legacy cleaning procedures developed for wet processing environments, such as meat or dairy plants, where heavy water use is standard. However, the rise of high-profile Salmonella outbreaks linked to dry products forced a regulatory and scientific pivot.

• Pre-2020s: Industry standards for "dry sanitation" were largely informal, varying wildly from plant to plant.
• January 2025: The U.S. Food and Drug Administration (FDA) released draft guidance specifically addressing sanitation programs for low-moisture food manufacturing. This guidance sought to establish a formal definition for "sanitation breaks"—a critical component in lot segregation and recall prevention.
• February 2026: Dr. Snyder and Nathan Mirdamadi published seminal work in Food Safety Magazine clarifying that wet sanitation is often the source of, rather than the solution to, microbial contamination.
• Present Day: The Cornell study serves as a "state of the industry" audit, revealing that despite the existence of newer FDA guidelines, widespread implementation has yet to take hold.

The study reveals that the definition of a "sanitation break" is currently a source of industry-wide confusion. Nearly half of the respondents (47 percent) define a break based on the method of cleaning, while others rely on product changeovers or the scope of the area cleaned. Only a fraction tie these breaks to the rigorous standard suggested by the FDA: a thorough cleaning followed by a verified sanitizing treatment of food-contact surfaces. This lack of standardization makes it difficult for companies to effectively segregate lots, meaning a single contamination event could lead to massive, unnecessary recalls.

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Supporting Data: The Humidity Blind Spot

One of the most alarming revelations of the Cornell study is the widespread uncertainty surrounding relative humidity (RH). If water is the catalyst for pathogen growth, humidity is the silent accelerator. Yet, the survey data paints a picture of a sector flying blind.

• Target RH Ambiguity: 32.5 percent of respondents were unsure of their facility’s target RH for dry processing zones, and 22.5 percent reported having only variable targets.
• The "Unknown" Ceiling: Nearly half (47.5 percent) admitted they did not know the highest RH levels their facilities experienced during normal operations.
• Chronic Moisture Events: Over 20 percent of participants reported that they still deal with condensation, equipment leaks, or water puddling at least once a month.

These statistics suggest that moisture management is not being treated with the same scientific rigor as pathogen testing. As Dr. Snyder and co-author Karl Thorson have previously argued, RH is a "critical environmental control" that is frequently overlooked. Elevated humidity promotes condensation, slows down drying processes, and complicates the handling of powders, which can then cake and create breeding grounds for bacteria.

For the 81 percent of respondents who do perform wet cleaning, the study shows they are attempting to mitigate the risk through active drying measures—such as fans, compressed air, or manual wiping. However, these methods carry their own risks. If the equipment used for drying (like a cloth) is not properly sanitized, it becomes a vector for cross-contamination, spreading the very pathogens it is intended to suppress.

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Official Responses and Industry Implications

The implications of this research are far-reaching. Regulatory bodies, including the FDA, are increasingly looking for "validated" sanitation protocols. When a manufacturer cannot define their sanitation break or does not monitor their RH, they are operating in a state of high vulnerability.

The study authors emphasize that while the survey was limited by a nonrandom sample of 40 professionals, it provides a crucial "exploratory characterization" of the industry. The findings suggest that companies must move away from "habit-based" cleaning and toward "data-driven" environmental control.

Key Recommendations for Manufacturers:

1. Standardize Definitions: Align facility-level sanitation break definitions with the latest FDA draft guidance to ensure regulatory compliance and better risk mitigation during product recalls.
2. Prioritize Humidity as a Barrier: Treat HVAC systems, dehumidifiers, and air-pressure balancing as critical food safety tools. Facilities should establish, document, and monitor target RH ranges with the same frequency as product testing.
3. Audit Wet Cleaning Practices: Evaluate whether wet-cleaning is truly necessary. If it must be performed, ensure that active drying protocols are validated to prevent residual moisture and secondary contamination.
4. Monitor the Environment, Not Just the Product: While finished-product testing for Salmonella is near-universal, the study notes that environmental monitoring programs must be robust enough to catch pathogens before they enter the food supply chain.

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Moving Toward a Culture of Dry Safety

The Cornell University study acts as a mirror held up to the LMF industry. While many manufacturers are making earnest efforts to maintain safety, the data suggests that these efforts are often siloed or based on outdated paradigms. The transition from "wet-cleaning habits" to "dry-sanitation science" is not merely a change in equipment; it is a change in the fundamental culture of the plant.

As the industry moves forward, the focus must shift toward the "hidden" variables of food safety. Pathogens do not respect traditional cleaning schedules, nor do they care about the convenience of a production line. By standardizing sanitation breaks, demystifying relative humidity, and acknowledging the risks of incidental water, the LMF industry can begin to close the gaps that have, for too long, allowed persistent pathogens to thrive.

The findings from the Cornell team serve as a call to action: in the world of low-moisture foods, dryness is not just a state of matter—it is a critical, measurable, and mandatory safety standard. Only by mastering the environment can manufacturers truly ensure the safety of the products on our shelves.