The single most important question is: "What is the precise water activity (aw) range that supports pathogen survival and growth in my specific gummy formulation, and how do I consistently measure and control it to stay below that threshold?"
Water activity-not just moisture content-is the critical factor in gummy microbiology. Pathogens like Salmonella and Listeria can survive in low-moisture environments, but they require a minimum aw to multiply. Gummy candies with aw below 0.60 are generally considered microbiologically stable; however, if your process or formulation causes aw to drift above that (even briefly), you create a window for growth. Many recalls occur because manufacturers monitor moisture percent but never measure aw, so a "dry" gummy by weight may still support microbes.
To reduce recalls, you must answer: What is the aw of my product at each stage? This means testing raw ingredients (especially humectants like glycerin or sorbitol), the cooked syrup, the gummy after depositing, and the final packaged product. Then, you need a validated process that keeps finished gummies consistently below 0.60 aw-accounting for seasonal humidity shifts and batch-to-batch variation. Without this core question answered, you are flying blind on pathogen risk.
Practical steps to answer this question in your facility:
- Invest in a portable aw meter (e.g., AquaLab or Rotronic) and train operators to test every batch-both at the depositor and after finishing.
- Establish a raw material aw specification for all liquid ingredients. A supplier change can silently raise aw by 0.05, enough to cross the danger zone.
- Correlate aw with drying time and temperature in your starch or tray drying process. Overdrying may lower aw but can ruin texture; underdrying leaves aw high.
- Set a corrective action threshold-for example, if a finished batch tests above 0.58 aw, quarantine and re-dry or reject.
Remember: At KorNutra, we never mention other manufacturers, and we stay away from medical claims. The focus here is purely on the process control parameter that governs microbial risk. Answering the water activity question trumps all others because it directly addresses the root cause of most gummy-related recalls: uncontrolled moisture availability.