UVC irradiation enables 99.999 percent sterilization of cans, lids, and spoons for baby food

The empty can sterilizer fills not only tinplate and combo cans but also plastic or glass containers with baby food. In doing so, it consumes only 0.75 kW of power, similar to the lid sterilizer. (Source: Swiss Can Machinery)

I am the Leerdosenentkeimer, additionally equipped with a lid conveyor belt LT 127, with eight UVC lamps installed with individual monitoring. Using UVC radiation, the DNA of the cells is deactivated, ensuring microbiological safety and the required hygiene. (Source: Swiss Can Machinery, sterilAir AG)

I am the Leerdosenentkeimer, additionally equipped with a lid conveyor belt LT 127, with eight UVC lamps installed with individual monitoring. Using UVC radiation, the DNA of the cells is deactivated, ensuring microbiological safety and the required hygiene. (Source: Swiss Can Machinery, sterilAir AG)

The lid opener is additionally equipped with a lid conveyor belt LT 127. Inside, four UVC lamps with individual monitoring ensure almost 100 percent sterilization of the container components. (Source: Swiss Can Machinery)

The Swiss company Swiss Can Machinery has recently introduced the world's first spoon dispenser for cans with an UVC disinfection rate of over 99.99 percent. (Source: Swiss Can Machinery, sterilAir AG)

The Swiss company Swiss Can Machinery has recently introduced the world's first spoon dispenser for cans with an UVC disinfection rate of over 99.99 percent. (Source: Swiss Can Machinery, sterilAir AG)

The spoon dispenser SD 153 is equipped with a stainless steel can conveyor belt. The spoon feed from chrome steel is carried out using a linear conveyor, and the spiral conveyor bin contains an additional vibration hopper with a filling volume of 100 liters. (Source: sterilAir AG)

The spoon dispenser SD 153 is equipped with a stainless steel can conveyor belt. The spoon feed from chrome steel is carried out via a linear conveyor, and the spiral conveyor container contains an additional vibration hopper with a filling volume of 100 liters. (Source: sterilAir AG)

The spoon dispenser SD 153 is equipped with a can conveyor belt made of stainless steel. The spoon feed from chrome steel is carried out via a linear conveyor, and the spiral conveyor hopper contains an additional vibration bunker with a filling volume of 100 liters. (Source: sterilAir AG)

As a critical point for bacteria, the surface of the spoon was defined. The disinfection rate was calculated according to the VDMA guideline using the reference germ Bacillus subtilis SA22 (DSM 4181). (Source: sterilAir AG)

"The advantages of UVC disinfection are certainly better known to our customers than to us. However, we are now in the fortunate position to accommodate any customer requests of this kind and to offer a customized machine with UVC sterilization," says Michael Grabher, Managing Director of Swiss Can Machinery AG. (Source: Swiss Can Machinery)

"Based on the timing or speed of the passing object, the distance to the UV radiation sources, and the power capacity of the UV units, we can calculate how many UV lamps need to be used to achieve a desired reduction of at least five log levels, that is, more than 99.999 percent," explains Martin Graupner, Managing Director of sterilAir AG.

Food for babies must meet the highest hygiene standards due to the vulnerability of their small bodies. Especially with sensitive products such as milk powder for infant formula, it is crucial to ensure that no germs are spread during filling. The Swiss specialist for filling and sealing containers with powder and dry products, Swiss Can Machinery, has recently introduced the world's first spoon dispenser for cans with an UVC disinfection rate of more than 99.999 percent. Together with additional UVC systems from sterilAir AG, cans for baby food, including lids and spoons, can now be reliably disinfected.

Since surface hygiene plays a central role in the food industry, UV components for sterilization are increasingly integrated directly into production systems. Using UVC radiation, the DNA of cells is photochemically degenerated, preventing cell division and proliferation. This ensures the required hygiene standards. "As an original equipment manufacturer, Swiss Can Machinery installs our UVC components in their filling systems—if necessary or desired by customers," explains Martin Graupner, Managing Director of sterilAir AG, about the cooperation. "Depending on the transport speed and germ reduction requirements, we calculate the individually necessary number of UVC units, which must be installed, for example, in a sterilization tunnel."

Since 2014, Swiss Can Machinery has implemented three installations for sterilizing baby food together with an expert in sterilization processes at customers in Estonia, Thailand, and Germany: UVC components from sterilAir AG were installed on a can sterilizer, a lid sterilizer, and a spoon dispenser. The low surface temperatures of the components allow their use even with heat-sensitive products such as thin packaging films. Additionally, operation is very economical, requiring little energy, and the UV lamps have a long service life. "The installation at the end customer is very simple because everything is pre-assembled in Switzerland. The customer only needs to turn on or operate the technology," explains Michael Grabher, Managing Director of Swiss Can Machinery AG.

Regarding performance, Grabher had specific requirements for the sterilization devices. For example, more than 99 percent (log 2) of bacteria should be killed. "We received very competent advice, and based on that, the right and customized product was recommended," he states with satisfaction. The detailed planning at the customer site is carried out in several steps: first, the requirements of the specific application are considered. Based on this, Swiss Can Machinery develops and constructs a suitable filling system in cooperation with sterilAir. sterilAir selects the appropriate product and integrates it into the matching filling machine before Swiss Can Machinery completes and tests it."

Installation of UVC components in can and lid sterilizers as well as spoon dispensers

Both the empty can sterilizer and the lid sterilizer, which is additionally equipped with a lid conveyor belt LT 127, have eight or four UVC lamps with individual monitoring installed. To order replacement lamps in time, a warning system for the end of lamp life is integrated. At the same time, the lamps are equipped with shatter protection, are HACCP and FDA compliant, and waterproof to IP 65. In case of damage or exceeding the lamp's service life, the machine automatically stops. The devices are designed for easy maintenance, so no major disassembly or modifications are necessary. They can be filled with sheet metal and composite cans; the empty can sterilizer also fills plastic or glass containers with baby food. Both systems consume only 0.75 kW of power.

The spoon dispenser SD 153, like the lid sterilizer, is equipped with a stainless steel can conveyor belt. The spoon feed is via a linear feeder, and the spiral feeder bowl contains an additional vibration bunker with a filling volume of 100 liters. Special sensors for detecting cans and spoons enable singulation of these items. Sterilization occurs within seconds.

Generation of UV load according to product conveyor speed

sterilAir was responsible for calculating and simulating the sterilization performance during the system installation: the critical point for bacteria was defined as the bottom surface of the spoon. The sterilization rate was calculated according to VDMA guidelines using the reference germ Bacillus subtilis SA22 (DSM 4181). The required dose (LD90) for this microorganism is 15.2 mJ/cm². Since the spoon sterilizer has a throughput of 60 pieces per minute, this results in a speed of 0.028 m/s for a single spoon. "Based on the cycle time or speed of the passing object, the distance, and the power capacity of the UV units relative to this object, we can calculate how many UVC light sources need to be used to achieve the desired reduction of at least five log levels, i.e., more than 99.999 percent," explains Graupner. In this case, the critical point was even reduced by 6.95 log levels, requiring a theoretical dose of 105.6 mJ/cm².

For the sterilization expert, the challenge was to generate sufficient UV load relative to the given product conveyor speed. This is essential to actually eliminate the target germ at the desired reduction rate. "UV sterilization is usually the last link in a chain that is considered in a system," says Graupner. "By this point, the entire production line, including the conveyor speed, has already been defined. Therefore, we need to adapt to our customers' requirements."

UVC irradiation combined with air cleaning guarantees maximum cleanliness during the filling process

Swiss Can Machinery has always used UVC sterilization. Additionally, the cans are also cleaned with air. They are turned upside down, blown twice with cleaned air, simultaneously suctioned, and then turned again. "However, both machines are necessary because UV cleaning, for example, cannot remove a screw, but blowing with rotation can," explains Grabher. "This means that neither UVC nor air cleaning replaces the other."

Grabher is very satisfied with the implementation of the projects—not only because of the low power consumption: "Our customers are probably even more aware of the benefits of UVC disinfection than we are. We are now in a good position to respond to any customer requests of this kind and offer a customized machine with UVC sterilization." The risk of injury to the eyes from UV radiation was also minimized with a task from sterilAir: an automatic shutdown when the devices are tilted ensures that operating personnel are not harmed.