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U professor in front of cheese-making machine

U dairy researcher Lloyd Metzger in front of the U's cheesemaking machine.

Making better cheddar

By Kate Tyler

From eNews, July 22, 2004

Making mozzarella stretchy and tasty enough to top off a pizza may not sound like the stuff of either high finance or high technology. Yet a gleaming new machine in the Food Science and Nutrition Building on the Twin Cities campus in St. Paul is testimony that high-quality cheesemaking is a major Minnesota industry. The brainchild of College of Human Ecology assistant professor Lloyd Metzger, the stainless steel colossus bedecked with hoses, vents, and porthole-shaped windows is essentially a state-of-the-art cheesemaking laboratory. Custom-made for the University and unique in the country, the "Scherping cheesemaking system" (named after the manufacturer) is a small-scale replica of the those used in industrial cheesemaking plants--the University's system processes 2,500 pounds of milk per batch compared with the 30,000-40,000 pounds a factory system can handle. For both University and industry folks, the partnership is a true win-win, says Metzger, who spent three years developing the U's machine with Sherping Systems. Dairy researchers at the University aim to generate knowledge that will apply to real industry situations, he points out, yet often have had to guess at how lab-based knowledge will translate to the factory floor. On the other side, he says, cheese manufacturers find it challenging to run experiments, try new techniques, or test alternative cheeses "because with their huge production systems, they'd have to throw out 40,000 pounds of milk for every test."

Cheese (and ice cream) treats

You can buy Minnesota Blue, Cheddar, Colby, Gouda or Havarti cheese for $2.50 to $4 a pound at the Food Science and Nutrition Dairy Sales Room Store on the Twin Cities campus in St. Paul. Or you can get a pint of Gopher Gold (French vanilla and raspberry swirl) ice cream for $1.50 and a half gallon tub for $4.

These dairy treats are made by U students and faculty during teaching demonstrations or as the control groups in lab experiments.

The store, located in room 166 of the Andrew Boss Meat Science Building, is open year-round on Wednesdays from 3 to 5 p.m. To find out what flavors are in stock before you visit, call 612-624-7776.

The U's computer-controlled system--with a vat, de-wheying/salting conveyer, and built-in cleaning equipment--allows cheesemakers to manipulate all of the steps that transform milk into cheese. These steps include standardizing milk to a desired fat content, pasteurizing it, and adding culture ("good" bacteria) for flavor and other properties. Special washing, salting, or other steps are added along the way depending on the cheese type. Then comes the ripening processes, which also vary-Swiss sits in a warm room to develop the gas that creates its familiar "eyes," mozzarella is stretched in a hot solution and then sliced or shredded, cheddar is pressed into blocks, wheels, or other shapes and stored in a cold vault. Varied uses Cheddar and mozzarella are the primary cheeses produced by Minnesota's large-scale manufacturers, but several firms are likely to use the U's system to explore the feasibility of expanding into new cheese varieties, such as parmesan or cottage cheese. Manufacturers also may use the U's system to tinker with the texture, flavor, appearance, and other functional characteristics of their cheese varieties, Metzger adds. Cheddar producers may wish to tweak the "firmness or flavor profile" of their products, for example, while mozzarella makers may aim to enhance the melty, stretchy tendencies of cheeses destined to top pizzas. Metzger, who grew up on a dairy farm in northwest Iowa, observes that several University studies have concluded that "in terms of economic benefit to rural Minnesota, no other industry comes close to dairy; the impact is nothing short of phenomenal."

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