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Sliced Cheese Inspection Using X-ray Technology

Peco-InspX is proud to be part of high-tech trends in food and beverage inspection. Today, we want to talk about food that is sometimes overlooked in the discussion: cheese.

Typically, sliced cheese comes in a plastic package, usually with a “re-seal” capability. The problems that cheese manufacturers tend to have are a bit different than what is seen in other applications, and it’s important to detail them. 

Some of the problems are intuitive. During the sealing process, it’s possible to get cheese in the seal itself. There are also a host of other foreign materials to find, of course. And cheese is a little more unique because gaskets can end up in the product. 

Cheese images can be “noisy”: grainy, with random variations in brightness or color. High-resolution systems can thankfully cut through the noise. 

The system we use to inspect cheese products is our high-resolution Allegro: a 20-inch top-down system that inspects 300 to 400 packs per minute!

 

Why is X-ray inspection so helpful?

(Watch the attached video to see images taken with a high-resolution system with a pitch size less than 0.2 mm. That’s much greater definition than you might be used to seeing with a 0.8 mm standard X-ray system!)

 

  

With high-resolution technology, you can see both the product and the packaging in the image. That’s important: you can’t inspect the seal if you can’t see the package itself. A lot of X-ray application detectors don’t have enough “dynamic range” to be able to find something that’s fairly thick (like a plastic seal) without burning out the part of the product that’s fairly thin. Everything is visible: the package, the product, and the contaminants. 

 

What makes high-resolution X-ray important? 

A common narrative around cheese is that everything findable is so low-density that X-ray systems aren’t necessary; the misconception is that they’re essentially “expensive metal detectors”. 

A high-resolution system is very different.

It should be able to find most to everything you would run into at a cheese product manufacturing plant. That’s because of the density discrimination sensitivity of the higher resolution X-ray system. 

X-ray systems work by using density differentiating detection: if something is more or less dense than something else, you can see it in the image. Things are the exact same density as the cheese won’t be visible. For instance, if a plastic contaminant is the same density as the cheese, you won’t find it. 

What’s great about a high-resolution system is that it can see smaller differences of density than a standard resolution system. We can see all contaminants; we can see varying densities. There’s no miracle of science – it’s greater sensitivity leading to better detection and better images.

 

What can the system find?

Rubber, plastic, stone, glass, tape, hair, and any metal except aluminum (for now) is easily detectable. And of course, we can find the infamous “cheese wire”, which is notoriously difficult to detect. What’s we can spot varies in size based on the contaminant. For example:  

  • Rubber: pieces as small as 0.8 mm
  • Low-density plastic: as small as 0.5 mm
  • Cheese wire: a piece that’s as small as 0.26 mm in diameter and 0.5 mm in length 

Hopefully, you’ve noticed – those are phenomenal detection capabilities. 

 

What about detecting ear protection?

Ear protection pieces can fall into cheese or packaging during production. Generally, ear protectors have some kind of plastic cord with foam at the ends to stick in your ears. The foam pieces are full of air, and the cords are standard plastic. A common diameter is about 1.6 mm. The entire cord is immensely detectable. 

 

Will there be false rejects?

As engineers, we know this sounds overly optimistic, but the truth is: there will be almost no false rejects.

The gap between the detection of the foreign material and the cheese is so wide that the false reject rate is somewhere between 1 in 20 and 1 in 40,000 – so, extremely low. The detection really is that strong.

 

What is seal detection like?

Sometimes cheese gets into the seal itself. We want to work with you to figure out what size of cheese trapped in the seal creates a sealing risk for customers. Then it’s easy to set a firm cut-off for what’s okay and what’s not. Then we can eliminate the sealing issues you’re having. 

If you look at the kind of quality control that modern resolution systems can provide for a cheese manufacturer, it’s night and day compared to the standard X-ray systems you might remember. High-resolution systems can make a real difference in the profitability of your company because you’ll have real-time quality controlling over the sealing.

 

And products in pouches?

We know that some cheese products come in paper pouches with metalized foil sprayed on them. These are sometimes the hardest to imagine. 

Some pouch pieces overlap; there can be micro leaks; sometimes there are wrinkles during the manufacturing process. Not all wrinkles are seal integrity risks, but we want to set our software up to eject those that are.  

With a single-lane system, we usually inspect these at 400 to 500 per minute; that means the image is taken at about 50 meters per minute. That’s operation friendly.

 

See for yourself!

To test our detection capabilities, send us your product! Click the link at the end of the video to receive instructions on how to do that. We’ll either do a confidential evaluation; or do it online and use it for the betterment of the cheese business. 

Remember that technology advances rapidly. Anything that’s not detectable today easily could be tomorrow. 

To learn more about our innovative company, please visit our website, Twitter, LinkedIn, or YouTube channel. We look forward to working with you!