Growth of Microorganisms in Food PDF

Growth of Microorganisms in Food Luca Fasolato Università degli Studi di Padova Dipartimento di Biomedicina Comparata e Alimentazione  Summary Microbial growth Microbial growth population phases Growth parameters Application :...

Growth of Microorganisms in Food Luca Fasolato Università degli Studi di Padova Dipartimento di Biomedicina Comparata e Alimentazione  Summary Microbial growth Microbial growth population phases Growth parameters Application : the shelf life A simple way to calculate the microbial growth parameters Log 10 CFU 5.18 LogCFU/g 5=100000 𝑦 = 𝑏 + 𝑚𝑥 4=10000 2.8 LogCFU/g 3=1000 Y INTERCEPT SLOPE 2=100 1=10 0 8 days days TIME A simple way to calculate the microbial growth parameters Log 10 CFU 5.18 = 2.8 + 𝑚8 TIME 5.18 LogCFU/g 5=100000 𝑦 = 𝑏 + 𝑚𝑥 4=10000 2.8 LogCFU/g 𝑦2 − 𝑦1 Final values 3=1000 𝑚= 𝑥2 − 𝑥1 Initial values Maximum Growth 2=100 rate μmax µmax =((5.18-2.8)/(8-0)) 1=10 log cfu/g/h 𝐿𝑜𝑔 𝑁𝑡 = 𝐿𝑜𝑔 𝑁0 + µ𝑡 0 8 days days TIME  Now we can predict the shelf life of pork steaks! TS Log 10 CFU log 𝑇 − log ⅈ 𝑇𝑆 = 𝐿𝐴𝐺 + 𝜇𝑚𝑎𝑥 7 5.18 LogCFU/g ? 5=100000 4=10000 2.8 LogCFU/g 3=1000 2=100 7 = 2.8 + 0.2975𝑥 7 − 2.8 𝑇𝑆 = 0 + 0.2975 1=10 𝑋 = 𝑇𝑆 0 days 𝑇𝑆 =? ? ? ? ? 8 days TIME ?  Processes Viable Enrichment uncontalbe medium  Exotoxins Extracellular production products Sporulation Biofilm, LPS Persistance Sporulazione maturation of LPS fermented products