Pasteurization Units (PU)
Compute the pasteurization units (PU) of a process, PU = t·10^((T − Tref)/z), the lethal time equivalent at a reference temperature. Widely used for beer and juice (Tref = 60 °C, z = 7 °C): a beer needs ~15 PU for microbiological stability. It lets you compare and control pasteurizers operating at different time-temperature combinations. Enter the time, the process temperature, the reference temperature and the z-value.
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Unidades de pasteurização (PU)
A pasteurização não esteriliza — apenas reduz a carga microbiana a níveis seguros e prolonga a vida de prateleira, preservando melhor sabor e nutrientes que a esterilização. As unidades de pasteurização (PU) medem a 'dose' de tratamento térmico: PU = t·10^((T − Tref)/z), o tempo letal equivalente a uma temperatura de referência. Na cerveja, o padrão é Tref = 60 °C e z = 7 °C, e busca-se em torno de 15 PU (faixa de 5 a 25, dependendo do risco) para estabilidade microbiológica sem 'gosto de pasteurizado'. Um túnel de pasteurização aplica isso aquecendo as garrafas com chuveiros de água quente e somando as PU acumuladas em cada zona — pasteurizar demais cozinha a cerveja, de menos arrisca contaminação. O conceito é análogo ao F₀ da esterilização, só que com referência mais branda. Informe o tempo, a temperatura do processo, a temperatura de referência e o z.
Related Tools
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.
Microbial Lethality
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.
Decimal Reduction Time (D-Value)
Compute the decimal reduction time (D-value) of a microorganism, D = t/(log N₀ − log N), the time needed, at a given temperature, to destroy 90% of the population (a one-log reduction). It is the fundamental parameter of thermal death kinetics in food processing: the larger the D, the more heat-resistant the microorganism. Enter the heating time and the initial and final populations.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.