Have some CRISPR with your Cheese!

Walking past the dairy aisle of the North Brunswick, NJ’s Trader Joe’s, I came across a section with items of different textures, colors and aromas. This was the artisan cheese section. I was here to pick up different types of cheeses that I rarely eat at home (I usually have Kraft American Cheese Singles or the Indian paneer at home) for a webinar on “Microbiology and Culture of Cheese” by Rutgers University professor, Dr. Max Häggblom. I managed to get Swiss Cheese, Cheddar, Brie and Bleu cheese, which had spots and veins, had a strong odor and a not-so-cheesy taste! I wasn’t daring enough to try a limburger!

Cheese is a staple food in many cultures. It is made from milk by curdling or souring milk that separates a watery liquid leaving behind a semi-solid substance, that is fresh cheese. The curdling is done by adding rennet, a groups of enzymes taken from the stomaches of calves (Häggblom, M. M., 2020). Other ingredients are added to make different cheeses. For example, the smelly but expensive bleu cheese is made with the mold Penicillium which gives it its distinct taste and texture. Limburger is made using Brevibacterium linens, the same bacteria that causes body odor and foot odor! The Indian paneer is made by adding vinegar or lemon juice to milk while heating it.

Cheese making was one of the first products to use genetically modified enzymes in its manufacturing process in the 90’s. Earlier, the manufacture of cheese required young calves to be killed since the rennet was harvested from these calves’ stomachs. In the 70’s, the public’s aversion to killing of young calves brought a supply and demand issue driving up costs so cheese makers turned to genetically modified organisms to produce the required enzymes in a lab. This enyzme, chymosin was responsible for rennet’s milk curdling properties. Scientists were able to introduce the chymosin producing gene into Escherichia coli, a type of mostly harmless bacteria that is found in your intestines, which was then used to manufacture large amount of rennet. The rennet formed artificially was more pure and cleaner, producing cheese with a better taste (Gadye, 2015).

The manufacture of cheese required healthy bacteria cultures. However, these bacteria cultures are vulnerable to viral infections. The viruses that attack bacteria are called bacteriophages. By using CRISPR techniques, bacterial genes were modified to incorporate pieces of the invading bacteriophages’ DNA and these are used to detect hostile viruses. Once these viruses are detected, a molecule called crRNA is used to bind with the protein Cas9 which is used to attack the virus’ DNA and interfere in its ability to infect the bacteria (Borealis, 2019). In this manner, the latest gene editing techniques are helping in non-medical fields such as dairy farming etc.

References

Häggblom, M. M. (2020, November 5) Microbiology and Culture of Cheese [Webinar]. Rutgers University School of Biochemistry and Microbiology.

Gadye, L. (2015, December 16). You Can Thank Genetic Engineering For Your Delicious Cheese. Io9. https://io9.gizmodo.com/you-can-thank-genetic-engineering-for-your-delicious-ch-1701156684

Borealis, S. (2019, July 25). CRISPR-Cas9: how the quest for better cheese revolutionized biological research –. ScienceBorealis.ca Blog. https://blog.scienceborealis.ca/crispr-cas9-how-the-quest-for-better-cheese-revolutionized-biological-research/

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