Introduction Not only is the human body colonized with a large variety of microorganisms, the environment people live in is also filled with countless bacteria and other microorganisms, which are known as environmental microbes. More importantly, since people spend the majority of their lifetime in indoor environments such as schools, houses, and hospitals, the indoor surface microbes hence play a crucial role in human health. Scientists have discovered that indoor microorganisms are associated with the Sick Building Syndrome (SBS) and other diseases which pose a significant threat to humans (Godish, 2001). One approach to investigate the indoor microorganisms is to study the abundance of microbes on a surface. Abundance is measured as the
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According to the fact that the most common bacteria, mesophiles, grow optimally in temperatures from 25 °C to 40 °C (Eddleman, 1998), cold surface areas such as the surface inside the refrigerator will hence have a very low abundance or colonization of bacteria because most bacteria do not prefer living in cold surface areas. Bacteria are likely to colonize other surface areas where they can be optimally grown. Following this hypothesis, the metal surface inside the refrigerator (6.6°C) of Room 2098 in the Science Lab Building (SLB) is chosen to be the sample site for testing low abundance of bacteria. This sample site was swabbed and streaked for single colonies on a nutrient agar plate. The colony count in this sample site supports the …show more content…
First, according to the group data about the colony count of the swabbed NA plates as shown in table 1, three out of four NA plates had no colonies visible. It is possible that the lack of growth of surface microbes can be due to improperly made NA plates. Streaking bacteria, Escherichia coli, onto the NA plate which originally had no growth of microbe can be performed to confirm the quality of NA plates. If the culture, Escherichia coli, forms colonies after 48 hours of inoculation at 30°C, this suggests that the lack of growth on the swabbed NA plates is indeed due to the absence of bacteria on that particular
According to the fact that the most common bacteria, mesophiles, grow optimally in temperatures from 25 °C to 40 °C (Eddleman, 1998), cold surface areas such as the surface inside the refrigerator will hence have a very low abundance or colonization of bacteria because most bacteria do not prefer living in cold surface areas. Bacteria are likely to colonize other surface areas where they can be optimally grown. Following this hypothesis, the metal surface inside the refrigerator (6.6°C) of Room 2098 in the Science Lab Building (SLB) is chosen to be the sample site for testing low abundance of bacteria. This sample site was swabbed and streaked for single colonies on a nutrient agar plate. The colony count in this sample site supports the …show more content…
First, according to the group data about the colony count of the swabbed NA plates as shown in table 1, three out of four NA plates had no colonies visible. It is possible that the lack of growth of surface microbes can be due to improperly made NA plates. Streaking bacteria, Escherichia coli, onto the NA plate which originally had no growth of microbe can be performed to confirm the quality of NA plates. If the culture, Escherichia coli, forms colonies after 48 hours of inoculation at 30°C, this suggests that the lack of growth on the swabbed NA plates is indeed due to the absence of bacteria on that particular