The Control Of Microbial Growth

1064 Words5 Pages
CONTROL OF MICROBIAL GROWTH Group # 3—2B1 Cabildo, Kathrina Marie E. Chiucinco, Shaina Eunice L. Ciocon, Jan Luziane Kristine Marie I. PHYSICAL METHOD CONTROL 60C CONTROL 100C 10 MIN 20 MIN 30 MIN 10 MIN 20 MIN 30MIN Escherichia coli + + + + + + + - Staphylococcus aureus + + + + + - - - The use of heat as a physical method rapidly destroys microorganisms. The killing rate of heat may be expressed as a function of time and temperature. The variety of temperature ranges are generally called as Cardinal temperatures which pertain to the estimated minimal, optimal, and maximum temperature ranges of bacterial growth. There are temperature ranges in which a bacterium can thrive on. The organisms involved in this part of the experiment are known to be classified as mesophiles, organisms that have a typical growth range of 20–48°C with an optimum of 37°C. The given results show that growth still occurred in the gram (-) and gram (+) bacteria Escherichia coli and Staphylococcus aureus, even after 30 minutes of water bath with 60°C. In E. coli, growth still occurred until the 20th minute of submerging. The effectivity of any temperature-mediated microbial control can be expressed in terms of thermal death point (TDP), the lowest temperature when all cells in a culture are killed within ten minutes and thermal death time (TDT) which refers to the time it takes to kill all cells at a given temperature. From the results observed, the thermal death time of E.
Open Document