Milk, juices and sports drinks in grab-and-go bottles are flying off retail shelves nationwide, yet a Michigan dairy was able to increase velocity by inserting a pop-up straw in 16-oz. PET containers, producing double-digit sales gains despite a bump in prices from 69 to 79 cents.

Lansing-based Quality Dairy claims unit sales of five single-serve milk products increased 14 percent in the first quarter this year when it inserted pop-up straws in packages sold in its 31 convenience stores. A 10 percent gain was posted for three 16-oz. juice products.

The price premium was more than enough to offset the cost of the straw, which was developed by the PopStraw Co., Roseville, Mich. A second dairy company will incorporate the pop-up straws in its packaging operations early next year.

The straws are fitted with a foam collar that's half the density of water, "so it really wants to pop up" when the cap is removed, explains Peter Murphy, president and cofounder of PopStraw. "It's like a life preserver. It lifts the whole straw almost two inches above the top of the container."

PopStraw sells the sterile, double-bagged straws to beverage companies and installs the equipment to package them at no charge.

The lock-and-release insertion system devised for the first two customers relies on compression and the straw's ribs to match fill speeds of 300 units a minute. A vibratory bowl orients straws and feeds them to a 31-in.-sq. machine that inserts the straw into a container under pressure. The bottle then is filled and capped, at which point an 18-in. machine squeezes the bottle to release the straw inside.

A second system capable of filling 900 units a minute also has been developed. It incorporates a hold-down device to prevent an unlocked straw from popping out prior to capping. The system was developed for glass containers and high-speed operations.

Next year, the company hopes to commercialize an injection molding system that uses MuCell, a polymer with microscopic air pockets that give straws buoyancy without a foam collar. That system would expand the straw's market to aseptic containers and carbonated soft drinks filled at 2,000 units per minute, Murphy says.