Episode 17: "Mr. Lactose," Kent Keller

Mr. Lactose talks water activity and lactose monohydrate

In this episode of Water in Food, we were joined by lactose specialist Kent Keller from Keller Technologies, Inc. Kent has been educating people in the lactose industry and upgrading lactose systems around the world for over 40 years. In 2000, Kent was honored with the American Dairy Product Institute's prestigious Award of Merit for his lifetime contributions to the lactose processing industry, and has even been called “Mr. Lactose.”

Kent gives us his unique insights into whey and lactose production, and how keeping a close eye on water activity is key in both industries.

Whey protein concentrate processing

After receiving a bachelor’s degree in chemical engineering, Keller took a job in Midland, Michigan at the Dow Chemical Company. Just six weeks out of college, he was given the opportunity to develop a new photochemical process for making a settling tetrabromide, which Dow patented and made into a commercial process.

While on draft deferment at Dow, Keller, who was assistant production manager of bromine products, decided to volunteer for the Peace Corps. This took him to a Mayan village in modern-day Belize to help organize a rice marketing co-op and demonstrate how to raise better livestock with lower costs.

Because of the poor protein sources in the village, protein malnutrition ran rampant among the children. This prompted Keller to enroll in Michigan State University upon his return with the goal to study new, cheaper methods to make protein. His thesis was on the fermentation of cheese whey to produce high-protein cattle feed supplements.

Keller realized that not only was whey good for cattle feed, but it’s a good source of high quality protein. And after a short stint at Cargill, he took a production manager position at one of the first plants to make whey protein concentrate on a commercial scale.

From whey to lactose production

While production manager, Keller made significant quantities of whey proteins using ultra-filtration, where about 20% of the milk proteins were recovered as whey. The remaining product was passed through a membrane to separate out the 80% lactose. That lactose was then used to make things like infant formula.

Unfortunately, this protein plant was shut down, but that allowed Keller to use his experience in whey to create a consulting company called Whey Systems, Inc., where he would help cheese plants create whey protein concentrate on-site instead of trucking the leftover whey to an off-site facility.

In the early days of his new company, the cheese plant owners were more interested in lactose production than whey protein concentrate. Unbeknownst to him at the time, when Keller’s processing plant was shut down, the country’s lactose production was cut by 50%, causing a 5-fold spike in the price of dried lactose.

After realizing the change in the market, he shifted his focus from WPC to lactose production, opening 40 processing plants around the world in his 20 years with Whey Systems, Inc.

Water activity and lactose

Simply put, lactose is the sugar inside milk. In the same way excess moisture can make a sack of table sugar go rock hard, it can cause major caking and clumping in lactose, too — lactose is even less soluble than sucrose. Importantly, lactose needs to be extremely dry, especially during shipment, where caking and molding can occur.

Before the creation of water activity meters, Keller was using a simple humidity gauge and thermometer to calculate the water activity of his dried lactose to set minimum specs to communicate to his clients. In 2000, he came across a water activity meter from METER Group, increasing the sensitivity of his measurements even more.

And it’s not enough to know how much water is in a shipment. Knowing the water activity of the lactose is more important than moisture content. Keller’s lactose is lactose monohydrate, which has 5% bound moisture with each crystal, so a moisture analysis that doesn’t take this water into account will give false findings. By measuring water activity, you’re only measuring the free moisture of the sample.

Generally, Keller sets a water activity target for lactose at about 0.2. Caking and clumping can start shortly after this at 0.3. Domestically shipped products might get by with water activity in that range, but overseas shipments have added complications that put that measurement out of range of acceptable levels.

At levels as low as 0.5, molding can occur. Once the mold starts to respire and break the lactose down into carbon dioxide and water, there’s a snowball effect that is hard to control, continually adding more free moisture into the environment. It’s very important to control free moisture from moving around the product.

By integrating (and in most cases developing) proper QA/QC techniques in processing a product as sensitive as lactose, Kent Keller has been able to change the lactose industry forever, without a doubt earning the moniker “Mr. Lactose.”