Cold Chain Bacterial Growth Simulator

Cold Chain Controls

Storage temperature 4°C

Organism / spoilage model

Initial contamination 2.0 log CFU/g

Simulation speed ×1

Live Readout

Food core temp

4.0°C

Elapsed time

0.0 h

Growth rate μ

0.000 /h

Population

2.00 log CFU/g

Safety status

SAFE

How it works

Bacterial growth rate depends strongly on temperature. This simulator uses the Ratkowsky square-root model, a standard tool in predictive food microbiology (used e.g. in the USDA Pathogen Modeling Program):

√μ = b · (T − T_min),   for T > T_min
N(t) = N₀ · e^(μt)      (exponential growth phase)

μ is the specific growth rate (per hour), T is the food's core temperature in °C, T_min is the theoretical no-growth floor for that organism, and b is an organism-specific rate constant fitted from real challenge-test data. The food's core temperature itself lags the surrounding storage/ambient temperature via simple thermal relaxation:

dT_core/dt = −k · (T_core − T_ambient)

so a brief door-open event does not instantly cook or freeze the product — it takes minutes to propagate, exactly like a real insulated package.

Storage temperature — the ambient air temperature the sample sits in (a home fridge is ≈4°C; USDA "danger zone" is 5–57°C).
Door-open breach — a 15-minute ambient spike to ~18°C, simulating a loading-dock or retail-case cold-chain break.
Organism — swaps b and T_min: Listeria can grow slowly even in a fridge (T_min ≈ −2.8°C); Salmonella needs ≥5.4°C; Pseudomonas is a common cold-tolerant spoilage organism.
Population dots — each visible sphere on the tray represents a fraction of the log-population; colour shifts green → amber → red as the count approaches the 7-log (10⁷ CFU/g) spoilage/illness threshold used as the safety cutoff here.

🌡 4.0°C

Low contamination Above safety threshold

⚠ Couldn't load the 3D engineThree.js failed to load from the CDN. Check your connection and reload.