F₀ Sterilization Value
Compute the F₀ value of a thermal process, F₀ = t·10^((T − 121.1)/z), the equivalent sterilization time at 121.1 °C (250 °F) with z = 10 °C, the reference for Clostridium botulinum. It is the universal 'currency' that compares thermal processes at different temperatures: an F₀ of 3 minutes is the minimum safety for low-acid canned foods (botulinum cook). Enter the time, the process temperature and the z-value.
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Valor de esterilização F₀
Como comparar um processo de 10 min a 121 °C com outro de 30 min a 115 °C? Pelo F₀, a 'moeda comum' da esterilização: F₀ = t·10^((T − 121,1)/z) converte qualquer binômio tempo-temperatura no tempo equivalente a 121,1 °C (250 °F), a referência mundial, usando z = 10 °C (típico de esporos bacterianos). Assim, processos diferentes que entregam o mesmo F₀ têm a mesma letalidade. O número mágico da indústria de enlatados de baixa acidez é F₀ = 3 minutos — o 'botulinic cook', que garante 12 reduções decimais do Clostridium botulinum (cujos esporos, se sobreviverem e germinarem numa lata sem oxigênio, produzem a toxina botulínica, uma das substâncias mais letais conhecidas). Processos reais miram F₀ bem acima de 3 (5 a 8) por margem de segurança. O cálculo real integra a letalidade ao longo de todo o histórico térmico do ponto mais frio da lata. Informe o tempo, a temperatura e o valor z.
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Compute the lethality rate (L-value) of a thermal process, L = 10^((T − Tref)/z), the factor indicating how many times faster (or slower) microbial destruction at a temperature T is than at the reference temperature. Integrated over time, the lethality gives the process F-value. It is the basis of the general-method sterilization calculation, which sums the lethality over the product's actual thermal history. Enter the temperature, the reference temperature and the z-value.
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