The Safety of X-ray Inspection of Food Products FAQs

A:  Most raw foods and ingredients originate in a natural environment such as a field, orchard, or farm. As the food is harvested, foreign objects such as stones or glass can be picked up and transported into the processing plant. Additionally, objects found in manufacturing facilities – such as metal and some very hard plastics – can find their way into the processing stream as the result of machinery or process failures. These risks and associated costs have driven more demanding detection policies worldwide. Food processors are integrating X-ray detection as part of an overall food safety program to help ensure that the end product is free from unwanted contaminants before it reaches the consumer.

A:  Food X-ray inspection systems are based on the density of the product and the contaminant. X-rays are simply light waves that we can’t see. X-rays have a very short wavelength, which corresponds to very high energy. As an X-ray penetrates a food product, it loses some of its energy. A dense area, such as a contaminant, will reduce the energy even further. As the X-ray exits the product, it reaches a sensor. The sensor then converts the energy signal into an image of the interior of the food product. Foreign matter appears as a darker shade of grey and helps identify foreign contaminants.

If you want to learn more about how food x-ray inspection systems work, download our free e-book, A Practical Guide to Metal Detection and X-ray Inspection of Foods. 

A:  Food X-ray inspection systems do not use potentially unsafe radioactive materials to generate the X-ray images. Rather, they rely on tubes that electrically generate the X-ray beam. The beam is directed at the object it is inspecting and a digital detector on the other side of that object creates an image for analysis. One of the advantages of this system, as opposed to one using a radioactive source, is that the X-ray energy stops immediately once the tube is turned off.

With that said, food X-ray systems do generate ionizing radiation so it is important to understand what levels are considered safe, what regulations might apply, what safety devices are used to meet these regulations, and what is done during manufacturing and installation to assure complete safety in all regards. But the manufactures take all measures to limit the amount of exposure by requiring mechanical shielding and curtains at the inlet and outlet of the machines to further reduce the amount of radiation leakage. It’s important that customers regularly check the curtains and replace them as they become worn.

A:  Although food X-ray systems generate radiation during their normal use, a worker standing at the control panel of an X-ray food inspection machine will likely not receive any radiation from the machine due to shielding. In fact, these machines emit 0.1 millirems (mrems) per hour or less and that emission is typically at the inlet or outlet where workers are not present. Multiplying 0.1 mrems per hour over the course of a 40-hour work week and a 50-week work year would imply a worker could be exposed to a total of 200 additional mrems per year in the worst case – significantly below the guideline for maximum exposure. The International Commission on Radiological Protection also states people can absorb 5,000 mrems annually (8X the natural dose) before radiation poses a health risk.

A:  In the course of our daily lives we all are subject to naturally occurring background radiation. In fact, natural radiation constitutes about half of the 620 mrems of radiation an average person experiences annually, according to the United States Nuclear Regulatory Commission. As we noted in the question above, the International Commission on Radiological Protection also states people can absorb 5,000 mrems annually (8X the natural dose) before radiation poses a health risk.

To put X-ray exposure during food production into perspective, here is the average radiation dose people receive from some common life experiences:

• Full body CT Scan = 1,000 mrem
• Natural/Cosmic = 310 mrem/year
• Trans-Atlantic Flight = 2.5 mrem
• Dental X-ray = 1.5 mrem
• Food X-ray Inspection = 0.1 mrem/hour*

**When in operation, food inspection systems can emit this maximum level of radiation per hour, typically very close to the input/output of the aperture only. Because human operators spend limited time in this location they would receive a much less (usually zero) radiation dose in an average work shift.

Download the white paper, X-ray Inspection of Food Products: The Safety Facts You Need to Know

A:  Countries around the world have regulatory standards to ensure X-ray safety. These regulations are in place to make sure that the X-ray equipment can be used by technicians and operators in all possible conditions. Some examples of key regulations by country are shown here:

Country                                     Regulatory Standard

• United States                  Code of Federal Regulations 21 Part 1020.40 (cabinet X-rays)
• Canada                           RED (Radiation Emitting Devices) Act
• United Kingdom              IRR 1999
• France                            NCF-74-100
• Spain                              UNE 73-302
• China                              GB18871-2002

Thermo Scientific X-ray inspection machines are always certified to these standards before selling and installing systems in these regions.