A temperature sensing device designed to mimic the thermal response characteristics of stored food products, providing temperature readings that approximate product conditions rather than ambient air conditions.
Also known as: glycol-buffered probe, between-pack probe, thermal buffer probe, simulant probe.
Why Simulant Sensors Exist
Air temperature and product temperature operate on fundamentally different timescales due to thermal mass differences. Air in a freezer changes temperature in minutes. Food product changes temperature in hours. A sensor that responds like air tells you about equipment performance. A sensor that responds like food tells you about product safety.
Food simulant sensors achieve this by placing the sensing element inside a material with thermal properties similar to food — typically propylene glycol at 50/50 concentration with water (specific heat ~3.4 kJ/kg·K, compared to frozen food at 1.5-2.5 kJ/kg·K).
The Core Distinction
Air sensors answer: “Is the equipment running correctly?”
Simulant sensors answer: “Is the product safe?”
Both questions matter. Neither replaces the other. Professional cold chain monitoring requires both — air sensors for equipment alarms and operational data, simulant sensors for product safety verification.
See also: Glycol Buffered Probe for detailed implementation guidance, physics explanation, and commercial options.
Related Terms: Glycol Buffered Probe, Temperature Monitoring System, Thermal Mass
Related Articles: Your Freezer Says -15°C. Your Product Says -6°C. Both Are Correct.