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 as big as a dairy herd in the Food Science and Nutrition Building on the University’s St. Paul campus is testimony that high-quality cheesemaking is a cornerstone of a major Minnesota industry.

The brainchild of CHE assistant professor Lloyd Metzger, the long stainlesssteel colossus bedecked with hoses, vents, and porthole-shaped windows is essentially a state-of-the-art cheesemaking laboratory, the heart of a new partnership between University researchers and the dairy manufacturers who loom large in the state’s economy. Custommade for the University and unique in the country, the computer-driven machine (called a “Scherping cheesemaking system” after its manufacturer is a meticulously designed small-scale replica of the truly massive systems used in industrial cheesemaking plants. The only significant difference is capacity: the University’s system processes 2,500 pounds of milk per batch as compared with the 30,000–40,000 pounds of factory systems.

For both University and industry folks, the partnership is a true win-win, says Metzger, a Ph.D.-trained dairy chemist who joined the Department of Food Science and Nutrition in July 2000 from a research post at General Mills. 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.”

As both research station and proving ground, the University’s small-scale Scherping system is ideal. “It’s not a big deal for manufacturers to scale up a cheesemaking procedure developed on our system since it’s representative of their industrial equipment,” observes Metzger, who spent three years working with Scherping Systems to develop the model. Scherping Systems built the machine at cost, and its construction and installation were paid for by the University-based Minnesota-South Dakota Dairy Foods Research Center, which Metzger directs.

Companies will pay reasonable user fees to lease the system, generating new revenue for University research and outreach programs. And the system’s state-of-the-art design makes it all the more attractive for industry use, says Metzger. He was fielding calls from potential users even as the 2,500-pound system arrived this past spring at the University’s loading dock (where, Metzger recalls, the enormous system had to be cut in half to get through the door of the food science pilot plant).

The computer-controlled system— which includes 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, adding “culture” (“good” bacteria) for flavor and other properties, adding an enzyme to convert milk from a liquid to a solid, cutting the gelled mass to remove the watery whey, then cooking the curd to drive out even more whey.

Special washing, salting, or other steps are added along the way depending on the cheese type. After manufacture, the ripening processes 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
Metzger can’t reveal the specifics of companies’ proprietary research agendas. Noting, though, that cheddar and mozzarella are the primary cheeses produced by Minnesota’s large-scale manufacturers, he says that 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 could do an alternate run at the end of the day to make those cheeses in their plants. But before they decide to enter new markets, they need to test how production would work and exactly what the yield would be,” Metzger explains.

Manufacturers also may use the U’s system to tinker with the texture, flavor, appearance, and other functional characteristics of their cheese varieties, says Metzger, especially of cheddar and mozzarella varieties, which dominate the market. 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. In addition, Metzger expects to use the system for his own research projects, which in the past have explored such issues as the effects of heat, acidity, and other manufacturing variables of cheese “performance” indicators such as melt and flow.

Artisan cheesemakers may use the U’s system as well, Metzger suggests. Small manufacturers of specialty cheeses may use the vat to work out manufacturing procedures for larger runs of some of their products. And, Metzger says, those whose cheeses demand handcrafting and old-fashioned open vats will also find help in the U pilot plant.

The pilot plant is a multifaceted research and testing facility maintained jointly by the College of Human Ecology and the College of Agricultural, Food, and Environmental Sciences. Expertly managed by experienced pilot plant manager Ray Miller, the plant also features traditional cheesemaking equipment—along with systems for making ice cream, dairy-related products such as milk-type beverages and cheese sauces, and other foods such as snack goods and cereals.

Pivotal partnership
“I think what we’re doing with the Scherping system is pivotal to helping make our Minnesota processors economically viable,” says Metzger, “which in turn is critical to Minnesota’s overall economic well-being.” 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.”

Alarmingly, says Metzger, Minnesota is “losing cow numbers fast—the number of dairy farms has declined substantially in the last decade. Now we’re starting to lose milk processors and cheese plants. When we lose our manufacturing facilities, then we see our Minnesota milk going to other places, such as New Mexico, Idaho, or California. Minnesota used to be one of the top five dairy manufacturing states, but we’re slowly working our way down the list.”

University-industry partnerships such as the Minnesota-South Dakota Dairy Foods Research Center and the Scherping cheesemaking system are powerful engines for the state’s economic vitality—while also reaping research and financial dividends for the University, Metzger says.

“As a public research university, and certainly in the College of Human Ecology, it’s our role to be at that interface where knowledge is applied to solve problems. The U is in a sense in customer service—our job is not just ‘we’re going to find out why and hey, you can use what we find if it suits you,’ but ‘let’s work together to identify relevant questions and come up with answers that matter.’ Take a look in our pilot plant and you can see that’s exactly what’s happening.” KT