Inspection efficiency on the incline

04 July 2021

Priding itself on the production efficiency in its two Dutch cheese factories, Vepo Cheese set out to upgrade all of its production lines with a new incline layout which included seven highly sensitive metal detectors.

Vepo Cheese approached Dutch manufacturer, Jansen Control Systems, to help design the compact incline inspection lines, each integrated with a vertical packaging machine. Vepo also wanted to look at metal detection options for the new lines. Gerard Schuurman, managing director at Jansen Control Systems suggested the Fortress Interceptor which can offer several advantages in cheese inspection applications.

Cheese can vary significantly in density and this, combined with the product effect, could react in different ways in the magnetic field of a traditional food metal detector. Schuurman said: “Not addressing product effect can lead to higher product waste. Vepo was especially interested by the Interceptor’s increased sensitivity and it also wanted a solution that could increase the inspection pace in order to keep up with growing production demands.”

Inspecting wet products presents cheese makers with a number of challenges. Water, like metal, is conductive. And cheese is inherently a wet and conductive product that also contains mineral content like salt. Accurate detection also depends on the size, shape and orientation of metal particles.

The Interceptor is said to override the propensity of ‘wet’ product effects that can drown out the signal, in particular the signals caused by a stainless-steel contaminant. Software algorithms make this possible by distinguishing between signals specific to the product and those that flag up anomalies. By singling out low-frequency signals, the Interceptor leaves the signal from stainless steel more readily identifiable in the higher-frequency range.

As a result, the system can pinpoint metal fragments with dimensions half those detectable with the previous generation of equipment, with greater reliability. The result of separating these two readings is any metal signal as a result of a genuine contamination isn’t swamped by product effect.

Maintaining efficiency

The ability to isolate rejected packs without interrupting the production flow was also important to Vepo. On previous inspection lines, Vepo didn’t have an automated reject system. If a contaminated pack was identified the belt would stop and an operative would have to intervene, remove the pack and restart the inspection process which reduced productivity.

Within two hours of installation of the lines, the factory was running at full capacity, accurately inspecting large quantities of grated cheese bags. Hugo van Put, technical operations manager at Vepo, quickly noticed that false positive rejects also fell after the new systems were installed. He said: “The metal detectors are really sensitive which gives us the confidence that the risk of contaminants is minimised, with less chance of a food safety issue. Having the double readings within the Interceptor system also lowers the risk of false positive rejects, which saves on food waste.”

Each metal detector features Contact Reporter software – data from each packaging line is collated in a common collection system, enabling quality assurance and production leaders to monitor processing and inspection performance from a centralised location. This automated record keeper solution helps the factory to keep track of and record logs for rejects, tests and process settings.