In vitro meat projectwww.maastrichthealthcampus.nl

Mark Post, Professor of Vascular Physiology and Tissue Engineering at Maastricht University’s Faculty of Health, Medicine and Life Science, is transforming stem cells into meat fit for consumption (in vitro meat). In October 2011, he launched a new project with the goal of producing an edible hamburger within a year.

The project follows from an earlier study in 2004 which received a 2 million euro grant from the Dutch government. The study was initiated by W. Van Eelen and implemented by a consortium of three universities (UvA, UU and TU/e) and a business representative (Meester Stegeman BV). The University of Amsterdam focused primarily on developing efficient culture mediums (agar) while Utrecht University focused on isolating stem cells and developing them into muscle cells. Mark Post, then a part-time professor at TU Eindhoven, developed a method with his team to stimulate the development of muscle cells (in size, not number) by training them using electrical currents. The study was concluded in 2009 with appetising results: the scientists had grown strips of meat from the muscle stem cells of mice that were 8 by 2 mm in size and consisted of millions of cells.

There are a number of crucial steps to growing in vitro meat: • First, muscle stem cells must be extracted from cows,

pigs or chickens. The current project uses cow stem cells obtained from offal or biopsies.

• The isolated stem cells must then be developed into muscle cells. As the project uses muscle stem cells, this happens almost automatically.

• The cells must then multiply, which requires a culture medium. This project works/experiments with commercially available culture mediums supplemented with calf serum. The next stage focuses on synthetic mediums or simple yet efficient culture mediums such as algae extract. This is done at the University of Amsterdam.

• Just like natural muscle cells, the cultured muscle cells must develop into strong muscle fibres/bundles in a process known as ‘bulking up’. They are attached to a biodegradable carrier of sugar polymers and trained by increasing the tension between two anchor points in the bioreactor.

• Once the muscle cells have increased in size, the tissue must be kept alive with a constant supply of nutrients. For the muscle strips in this project, regularly changing the culture medium is enough. Growing thicker slabs of meat will require the development of a canal system made from biodegradable polymers (sugar chains). This will mimic the effect of blood running through the veins, but in this case with a culture medium.

• To transform this tissue into an edible product, the taste and texture will have to be improved. This is done by getting the tissue to resemble ‘natural’ meat as much as possible in terms of protein composition, fat tissue, etc. If this is not enough, accepted food technology methods will be applied to improve the taste and texture.

• Once these steps have been taken, we will have edible muscle tissue that can be ground into minced meat to create the very first in vitro hamburger!

The researchers are now working on scaling up production with existing techniques. A new project will soon be launched to grow fat tissue and another to increase myoglobin expression in the meat.

The in vitro meat team consists of Professor Mark and two analysts. The project is fully financed through private funds, with a 300,000 euro investment for the coming year.

Three peTri dishes, each wiTh a muscle sTrip anchored

beTween Two five-cornered pieces of velcro.

by elecTrically sTimulaTing These muscle cells (lefT) The

young muscle cells (middle) develop inTo maTure and

powerful muscle cells wiTh characTerisTic Transverse

sTriaTions (righT).

more information:Professor Mark PostE: secretariaat-fys@maastrichtuniversity.nl