Calculates the combined microbial stability of a food product by summing hurdle scores for water activity, pH, temperature, and preservatives. Hurdle technology uses sub-lethal levels of multiple stresses to achieve stability without extreme single treatments — combinations of Aw < 0.93 + pH < 5.0 + refrigeration prevent most spoilage pathogens.
Inputs
Aw
Reference formula or conversion factor shown for context.
Ph
Reference formula or conversion factor shown for context.
Temp C
Thermal state of the substance. Check whether the formula needs Celsius, Fahrenheit, or Kelvin (K = °C + 273.15).
Salt Pct
Amount of solute per unit volume. Higher concentration = more solute dissolved.
Co2 Pct
Reference formula or conversion factor shown for context.
Results
combined hurdle score
A numerical rating from the scoring model in use.
estimated relative shelf life (days)
The value at the specified point or condition.
water activity hurdle score
Water activity (aw) — the ratio of vapour pressure to pure water at the same temperature. Above 0.85: microbiological growth risk. Below 0.6: most microbes cannot grow.