What Food Consultants Catch That Your Team Is Missing

Food safety failures rarely start with a dramatic event. Most begin with a small moisture decision that nobody questioned until months later, when a product is clumping on the shelf, failing a stability test, or triggering a recall.

Rachel Zemser, food consultant and founder of A la Carte Connections, sees many different food facilities making similar mistakes. So does Zachary Cartwright, principal food scientist at AQUALAB. In a recent webinar on moisture management from start to finish, the two shared what well-run teams do differently and where everyone else tends to fall short.

Here are the four most common mistakes they see.

1. Moisture management starts too late

The most common mistake Zemser sees: teams treating moisture as a production problem instead of a formulation decision.

"Water activity targets and moisture management really need to start in the lab during the R&D formulation process," she said. "Not after scale-up, not during production runs. All of the decisions have to be made beforehand."

Every decision downstream inherits the moisture profile built into the formula. When teams try to fix it later, they are not solving a production problem. They are reversing a design decision under pressure.

This is especially true when reformulating to remove preservatives. The water activity target may stay the same, but the chemistry holding it in place changes. Preservatives often bind water, and removing them without compensation can shift the moisture balance enough to create microbial risk. Natural and organic formulations face this challenge constantly, with fewer preservation tools and less room for error.

2. Assuming dry ingredients are safe

Low moisture does not equal low risk. It is one of the most persistent misconceptions in food manufacturing.

The Blackstone Products recall in May 2026 is a recent example. A dry, shelf-stable Parmesan ranch seasoning was recalled after a dry milk powder ingredient tested positive for Salmonella. The ingredient was dry. The product looked safe on paper.

The issue is not that dry ingredients are inherently dangerous. It is what happens when they enter a process where water activity rises. Organisms cannot grow without water. But if a contaminated low-moisture ingredient reaches an environment where water activity climbs above 0.85, pathogenic growth becomes possible.Think of flour in batter or peanut butter in a mixed product. The ingredient profile at receiving tells you nothing about the full system risk.

Tracing moisture through the entire product system, not just at the ingredient level, is what separates reactive teams from proactive ones.

3. Testing at only one point in the process

Even teams that do measure water activity tend to measure it in one place: the end of the line. By then, there is nothing actionable to do with a bad result.

Zemser recommends two earlier checkpoints that most facilities are missing.

The first is incoming ingredients. A COA from a supplier is not a measurement as specs can drift and shipping conditions vary. A moisture-contributing ingredient arriving even slightly out of spec can affect the entire batch. Checking it at receiving is the simplest intervention available.

The second is a mid-process check before final forming or packaging. "If those results come back high, then what?" Zemser said. "Nothing can be done at that point. It's just wasted product and wasted money." Catching an off-spec batch before it goes through forming equipment saves significantly more than catching it on a finished product test.

There is also a timing issue in R&D that catches teams off guard: a water activity reading taken immediately after production is not the final number. Moisture equilibrates inside a product over hours and days. Day-zero results are an early indicator, not a confirmed spec. Real limits need to be set based on where the product lands at day one or beyond.

4. No in-house water activity meter

Asked what she looks for first when walking into a facility without a strong moisture program, Zemser does not hesitate.

"If they don't have a water activity unit in-house, that is the number one big red flag for me."

Without a meter on site, there are no real-time measurements, no CCPs built around water activity, and no receiving protocols that include moisture checks. The program cannot exist without the tool. Teams sending samples to an outside lab after a production run is complete are not getting slow results. They are getting results they cannot act on.

Moisture management is a system, not a checkpoint

What separates teams that stay ahead of moisture problems from those that react to them is not more testing. It is treating moisture as a connected system: water activity targets set in R&D, ingredients verified at receiving, mid-process checks before forming, and packaging validated for the moisture barrier it actually provides.

The full webinar covers each of these stages in detail, including how Cartwright and Zemser approach packaging decisions, sustainable material transitions, and making moisture measurement practical at production speed.

Frequently Asked Questions

What is water activity and why does it matter for food safety?

Water activity (a_w) measures the amount of unbound water available in a food product to support microbial growth, chemical reactions, and physical changes. A water activity above 0.85 can allow pathogenic organisms like Salmonella to grow, even in products that appear dry. Controlling water activity is the foundation of shelf stability, food safety compliance, and preventing costly recalls.

At what water activity level do pathogens like Salmonella grow?

Most bacterial pathogens, including Salmonella, require a water activity above 0.85 to grow. Mold growth can begin at a_w 0.70 and above, while some xerophilic molds can grow at even lower levels. This is why a dry appearance is not a reliable safety indicator; only measuring water activity with a calibrated meter confirms whether a product is truly in a safe range.

When should water activity be measured during production?

Best practice is to measure water activity at three points: (1) at ingredient receiving to verify incoming materials meet spec, (2) at a mid-process checkpoint before final forming or packaging, and (3) on finished product, though not at day zero, since moisture equilibrates over hours and days after production. Measuring only at the end of the line leaves no room for corrective action.

Can dry ingredients still pose a microbial risk?

Yes. A dry ingredient is low-risk in isolation, but its safety profile changes the moment it enters a wetter system. A contaminated low-moisture ingredient (like a dry milk powder) can introduce pathogens that become dangerous if the finished product's water activity rises above critical thresholds during processing, mixing, or storage. Tracing moisture through the full product system is essential.

Does removing preservatives affect water activity targets?

Yes. Preservatives often bind water, helping to maintain a product's water activity below critical limits. When they are removed, as in natural or clean-label reformulations, the water-binding function disappears. If the formula isn't adjusted to compensate, water activity can rise enough to create microbial risk. This is one of the most common issues food scientists encounter in clean-label product development.

What should a food facility look for when choosing a water activity meter?

A food facility should prioritize accuracy, speed, and ease of use at production scale. Key factors include measurement range (0.0–1.0 a_w), repeatability, calibration traceability, and the ability to integrate readings into a quality control workflow. Having an in-house meter, rather than relying on an external lab, is the most critical step, as it enables real-time measurements that can actually inform decisions before product is committed.

Why is moisture management considered a system, not a single test?

Because moisture affects every stage of a product's life: the water activity target must be built into the formula during R&D, verified when ingredients arrive, checked mid-process before forming, and confirmed against the packaging barrier's actual moisture transmission rate. A single test at the end of the line reveals a problem too late to act on. A connected system of checkpoints makes moisture risk manageable and predictable.