Little Known Use for Ultrasound, #473: Detecting Foreign Bodies in Cheese

IMAGE: Vincent Leemans and Marie-France Destain

I was just doing a Google Scholar search for “cheese” (because why not?) and came across an article published in the February 2009 issue of the Journal of Food Engineering which describes a new method—why yes, previous research on this topic has been done—of identifying unwanted objects accidentally buried in cheese. I wasn’t aware that cheese often came with unwanted objects buried in it, but the writers of the article contend this is a major problem in the food industry, so maybe I’ve just been lucky.

You can read the abstract of the paper here, but I’ll sum up. The scientists stuck the inner plastic core of a ballpoint pen through the crust and about halfway into a block of Belgian cheese, which in case you are interested (I was), they describe as the following: “an enzyme coagulated, surface ripened, semi-soft cheese of Trappist type."*

Then they blasted the cheese with a high-frequency sound, checked how loud it was when it came out the other side, and measured the echo, if any, that came back to the original sensor. Comparing these results with those produced by a block of cheese lacking in foreign bodies, they were able to conclude that the ultrasonic device was, in fact, a relatively robust means of detecting the pen core. I know! How awesome is that?

Also awesome: the list of concerns the researchers expressed with this method of internal defect-detection, which include “the high attenuation of the signal due to the cheese texture (and especially the crust),” and the fact that “the raw signal was dependant on the temperature and on the maturity of the cheese.” Tell me food engineers don’t have the best jobs in the world.

*You will be glad to note that the ultrasonic cheese testers confirmed this classification by consulting a scholarly work entitled Cheese Rheology and Texture.