Swiss Cheese Niche

From MicrobeWiki, the student-edited microbiology resource

Description of Niche

Where located?

Physical Conditions?

What are the conditions in your niche? Temperature, pressure, pH, moisture, etc.

Influence by Adjacent Communities (if any)

Is your niche close to another niche or influenced by another community of organisms?

Conditions under which the environment changes

Do any of the physical conditions change? Are there chemicals, other organisms, nutrients, etc. that might change the community of your niche.

Who lives there?

Which microbes are present?

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Within the Swiss Cheese environment lives three types of microbes of the genus lactobacillus, streptococcus, and propionibacteria.

Lactobacillus is a gram-positive bacteria that is always found within Swiss cheese due to its ability to provide texture and sharpness of the cheese. Different types of strains of lactobacillus(L. helveticus, L. casei, L. bulgaricus) live in Swiss cheese but the more commonly known bacteria is the strain lactobacills helveticus. This microbe is part of the lactic acid family of bacteria by converting lactose present in the cheese to lactic acid. [1]

Do the microbes that are present interact with each other?

Describe any negative (competition) or positive (symbiosis) behavior


Lactobacillus helveticus is mainly involved with Streptococcus thermophilus in controlling the pH level of the Swiss cheese environment through their fermentation of lactose. The Swiss cheese enivronment changes temperatures due to the pastuerization process and in its intial stages Streptococcus thermophilus is the more dominant bacteria in the cheese. However since makers of Swiss cheese allow it to sit at room temperature for the ripening process allows for the growth of lactobacillus helveticus. Since room temperature is slightly off from the optimum growth temperature for lactobacillus helveticus, the microbe is slowly able to grow. When L. helveticus reaches its maximum growth or reaches the stationary phase it begins to lyse and starts to affect the viability of Streptococcus thermophilus. There is correlation between the survivability of Lactobacillus and Streptococcus but there are no specifics as to why the correlations occur. [2]

Do the microbes change their environment?

Do they alter pH, attach to surfaces, secrete anything, etc. etc.

Do the microbes carry out any metabolism that affects their environment?

Do they ferment sugars to produce acid, break down large molecules, fix nitrogen, etc. etc.


Current Research

Enter summaries of the most recent research. You may find it more appropriate to include this as a subsection under several of your other sections rather than separately here at the end. You should include at least FOUR topics of research and summarize each in terms of the question being asked, the results so far, and the topics for future study. (more will be expected from larger groups than from smaller groups)


References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.


[1] White, S.R., Broadbent, J.R., Oberg, C.J., McMahon, D.J. "Effect of Lactobacillus helveticus and Propionibacterium freudenrichii ssp. shermanii combinations on propensity for split defect in Swiss cheese". Journal of Dairy Science. 2003 Mar;86(3):719-27.

Edited by , students of Rachel Larsen