Say CHEESE: The real GMO picture

I remember in college taking a food microbiology class.  How hard could a class about food be?   Food is not complicated is it?  Then we started learning all kinds of things about pH, fermentation, enzymes, bacteria, etc and how those things interact with food.   I quickly learned that food is complicated especially food that needs to go through a biological process before the final product is available.   A perfect example of a food like this is cheese!  Look at this process in the figure below.  I quickly realized that the science of cheese is not as straightforward as I first thought.

http://wiki.ubc.ca/File:Cheese-production.gif

For an introduction at cheese making, here is a great article:   http://www.cheesescience.net/2007/07/introduction-to-cheese-science_30.html .  The site summarizes very nicely in one sentence a very simple definition of the cheese making process. "Cheese manufacture, which dates from 6000-7000 BC, is essentially a method for preserving the nutritive value of milk through fermentation, removal of moisture and addition of salt."

I wanted to focus on one step of the cheese process:  the coagulation step.   Say what? Remember this nursery ryhyme growing up?

https://en.wikipedia.org/wiki/Little_Miss_Muffet#/media/File:Little_Miss_Muffet_1_-_WW_Denslow_-_Project_Gutenberg_etext_18546.jpg

Miss Muffet likes the results of coagulation.  The coagulation step is when the milk "clots."  You may have heard the same term referenced with blood.  When our blood clots it is coagulating.  Milk coagulation is when the the casein protein in milk is broken down so that the milk curdles.  The milk separates into solid curds and liquid whey just like like Miss Muffet likes.   Milk does not just spontaneously separate into curds and whey.  There are so many types of cheeses and thus there are multiple ways of making milk coagulate.  In many of the popular cheeses, including swiss, cheddar, and mozzarella an enzyme is added to the milk to start the breakdown of the casein protein, This special enzyme is called rennet.

http://slowfoodwellesleysnail.blogspot.com/2014/01/wasiks-cheese-lecture.html

Rennet is an important enzyme in the business of making cheese so where does it come from?   Nature first provided the answer.   Calves that drinks their mother's milk need to be able to break it down sand so baby calves produce the enzymes, ie rennet to break down the milk.  The enzyme occurs naturally in calves stomachs and cheese makers took advantage.   Rennet is harvested from a calf's fourth stomach, a process that involves killing the animal.  Harvesting the stomach is a by-product of the veil industry.  The rennet that is harvested from a calf's stomach is a mixture of chymosin, pepsin and other proteins.  Chymosin is the most important part of the rennet to coagulate milk.

The animal rights movement started to take off in the 1960s.  Due to that movement the rennet price became very unstable as there was a resistance to killing calves to harvest stomachs.  Whether you have a problem with the animal slaughter or not, the fact remains that getting the rennet from calf's was a laborious process and costly endeavor.  With pressure of animal right groups, cheese producers tried to find alternative way to obtain rennet.

Welcome to the world of GMO microbes.   Scientists discovered in the 1980s a way to genetically modify bacteria with one gene from the bovine genome to produce chymosin , the main milk caogulation factor found in rennet.    TheGMO microbes are grown in liquid culture and as they grow and express the bovine gene they release chymosin into the liquid culture.  The liquid is gathered and the chymosin is purified and then used to make cheese.   The purified chymosin is called FPC (Fermentation-produced chymosin)  and was approved by the FDA in 1990.

http://www.nytimes.com/1990/03/25/us/gene-altered-item-approved-by-fda.html

Today, 90% of the cheese made in US use FPC.  Scientists now synthesize (or artificially make) the gene needed to make FPC without actually using DNA derived directly from the animal.   The use of GMOs to produce FPC is an important use of biotechnolgy in that it was used to solve a problem no matter where you stand on animal rights.   It is a cheaper solution that produces an even purer form of the enzyme needed to make cheese.

The GMO bacteria are releasing the enzyme and it is purified.  No actual GMO bacteria are put into the cheese and thus even if GMO labeling comes along cheese may not be on that list.   The cheese itself does not contain any genetically modified organisms, just the purified enzyme from a GMO.   In Vermont, a law is set to go active in July 2016 requiring GMO labeling of food in that state.  Guess what will not have a GMO label?  You guessed it.  Cheese will be exempt from that law.  Yet make no mistake GMOs are being used to help make certain types cheeses and it is a safe and cost effective solution.

So next time you eat cheese, think about the beneficial effects of GMOs.  The next time someonce says, "Say Cheese!" then share with them the real picture.   GMOs have been a part of cheese making since the 90s with nothing but positive results.   Eat some cheese and advocate for GMOs.