Bacteria Ecology Essay

After several biochemical tests, Unknown Bacteria #30 was identified as Staphylococcus aureus. After growing the bacteria on Nutrient Agar to ensure a pure sample, it was Gram stained to determine morphology and arrangement. It was observed to be a Gram positive staphylococci. Then, the bacteria was inoculated onto a Mannitol Salt Agar plate. After incubation, it was observed to have bacterial growth and the agar was yellow in color. According to the lab manual (2), MSA contains 7.5% NaCl and phenol red, a pH indicator. Due to the salt content, MSA is selective for salt-tolerant bacteria and the phenol red allows MSA to differentiate for mannitol fermentation. Mannitol fermentation is indicated by a yellow color change, which is the result of acidic byproducts changing the pH of the agar. The results showed that the bacteria was both salt-tolerant and able to ferment mannitol.

After approximately 2 minutes, the test tubes were removed from the water and placed into the test tube rack for us to observe any changes to the solutions. The resulting states and colors of the test tubes were as follows: The negative control water was clear and blue in color; coconut milk was opaque with a dark orange precipitate in the bottom and orange through the rest of its solution; karo syrup was opaque with a dark orange precipitate in the bottom and orange throughout its solution; potato chips solution remained cloudy with no precipitate and was blue in solution; peanut butter solution was opaque with a brown precipitate in the bottom and brown through its solution; and the banana baby food

It contains the mineral calcium, which build bones and keep them healthy. Osteoporosis is a condition where your bones are pourous and break or fracture very easily. Drinking milk and obtaining calcium helps prevent this in a major way. Protein is also found in milk, and is also extremely important.. Protein is used by your body to repair and make tissue, such as your hair and nails, and is also used to make enzymes, such as lactase, to speed up chemical reactions in your body. One last thing found in protein is potassium. Potassium helps maintain mineral and water throughout your body, can help control muscle growth and plays a big role in nerve function. Regular drinking milk is broken into four main types, with countless products branching off. These four types are whole milk, 1% milk, 2% milk, and skim milk. The types are divided by their fat contents (whole being the highest in fat, skim being the lowest). The brand of milk that will be used in this experiment is Horizon. This brand is part of the National Organic Program, so the cows producing the milk will not be genetically modified. This means the cows will not be given any hormones or preservatives, which could potentially effect the milk, and how the lactase responds to

The results suggest that pasteurization kills most pathogens in milk by brief exposure to relatively high temperature. This was demonstrated most beneficially with the 10-6 and 10-7 dilutions wherein the raw milk exhibited 284,000,000 cells/mL and 440,000,000 cells/mL respectively and the pasteurized milk had too few cell colony forming units to even count. Unpasteurized milk is not healthy for people to drink. For example, in a study performed in December of 2001, the bacteria Campylobacter jejuni, a microaerophilic bacteria commonly found in animal feces, was found in unpasteurized milk at an organic dairy farm in Wisconsin and caused 75 people, ages 2 to 63, to become ill.

The purpose of this lab was to discover which molecules are found in certain foods. I expected to learn more about the molecules that we tested for, which were simple sugar, starch, and protein. I also expected to learn more about macromolecules, since simple sugar and starch are both carbohydrates, and I expected to learn more about what makes up food. If each food is tested for simple sugar, starch, and protein, then milk will have simple sugars and protein, crackers will have simple sugars, bananas will have starch and simple sugars, and egg whiles will have protein.

Both literature values for the total carbohydrate concentrations in the milk samples were 45.85 mg/mL. This does not compare satisfactorily with our experimental total carbohydrate concentration for milk at 0.3682 mg/mL, and for lactase-treated milk at 0.0809 mg/mL. With these numbers equating only a fraction of the desired concentration values, there is significant error that occurred in the aniline assay. Perhaps the lactose present in the milk samples was not efficiently hydrolyzed to its glucose and galactose monomers, leaving little glucose to analyze through absorbance analysis. Other errors include the preparation of inaccurate dilutions, which could explain the lack of linearity in our standard samples when forming a line of best-fit

Our materials for the experiment was Solution A, Solution B, 2% milk, Coca-Cola, synthetic white flower, Phenolphthalein, butter, ice, magnesium ribbon, and ammonia.

In this lab we began by identifying the independent and dependent variables for our experiment, we eventually chose the milk type for are independent variable and the reaction time as our dependent variable. We then ran three trials on whole,1%, and fat free milk and collected quantitative data, concluding our experiment.

List all of the products that could possibly be affected by a problem in the U.S. milk supply

 When milk becomes acidic the proteins and fats in the milk become entangled with each other, this leads to the separation of the milk, creating curd cheese. “Normally, little groupings of casein float around in the milk without bonding to anything. These groupings have a negative charge, which makes them repel other groupings

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This data refers to the hypothesis as full cream milk had a faster rate of reaction due to the amount of fat present in the milk. This was measured by using a pH probe as it was

Unlike what we have been thought, milk is unhealthy and it will cause many different diseases in human’s body. Even though that they try to limit the bacteria in raw milk before and after milking, but they just can lower the level of bacteria, they can’t remove all of it, and by drinking milk we transfer diseases to our body (Garedew et al, 2012, p 950). Before milking they will sterilize cow’s breast and also they will inject antibiotics to lower the level of bacteria in cow’s body. They also use sterilize milking equipment so the bacteria available on the equipment will not reach cow’s breast and directly milk. With all those sterilized processes they still need to do the pasteurization process because of

There are three types of environments in which cells are located which include isotonic, hypotonic and hypertonic. In an isotonic environment, the amount of water and solute are the same both inside and outside of the cell. As water drifts into the a cell, the same amount flows out creating a balanced environment both inside and outside of the cell. When there is a high level of water on the outside of the cell and a high amount of solute inside the cell, water will be drawn inside of the cell creating a hypotonic solution. The increase in water inside the cell causes the cell to become engorged and erupt. In a

Another purpose of this experiment is to stress the importance of knowing the identity of a microorganism. Knowing the species of microorganism present in a sample provides a