Pilots and airline cabin crew are typically exposed to more radiation in the course of their work than operators of x-ray food inspection machines. None of these groups of people, however, receive levels of radiation that are at all close to being harmful. This and many more facts are outlined in a white paper from Eagle Product Inspection (Eagle), a global pioneer of product inspection technology including x-ray and inline fat analysis. The company hopes that this white paper will alleviate any reservations about the safety of food that has been through an x-ray inspection machine for quality control purposes, and about the safety of operators of such machines.
The white paper, titled “How Safe is X-ray Inspection of Food?”, explains the nature of x-rays compared to radioactive material, and points out that the level of radiation used for x-ray inspection in the food industry is extremely low. In addition, the white paper explains in detail the highly regulated nature of x-ray inspection equipment construction, which in many instances goes beyond the standards laid down in legislation around the world.
“X-ray inspection of food has been adopted by increasing numbers of food manufacturers due to its efficiency and accuracy in detecting foreign bodies such as glass and stones within food products. It can simultaneously perform a wide range of in-line quality checks such as monitoring fill levels, inspecting seal integrity, and checking for damaged products at high line speeds,” says Kyle Thomas, strategic business unit manager, Eagle Product Inspection. “The evidence shows that food that is good to eat before being x-rayed is just as tasty and nutritional afterwards. Plus, operators working with x-ray inspection systems are protected by legislation and by expert equipment design. In conclusion, consumers and operators have nothing to be concerned about.”
X-ray versus radiation
To begin with, it is important to understand the difference between x-ray and radioactivity. While x-rays are a form of electromagnetic radiation, they are electrically generated, and can be switched on and off. Radioactive materials such as uranium however are very different. They continuously emit radiation in the form of alpha and beta particles and gamma rays, and cannot be switched off.
In everyday life, every person on Earth is exposed to various forms of radiation, known as background radiation. Around half of this comes from radon gas, which seeps out of uranium-containing soils and rocks, typically granite. Other sources of radiation that reach humans come from space (cosmic radiation), medical radiation (chest and dental x-rays being the chief source), and internal radiation, picked up by inhaling or ingesting tiny particles of radioactive material, usually in the form of fine dust.
To put this into context, it is necessary to look at accrued radiation doses. The International System of Units (SI) for radiation dosage is the Sievert (Sv), however occupational exposure levels are typically so low that millisieverts (mSv: a thousandth of a Sievert) and microsieverts (µSv: a millionth of a Sievert) are commonly used. The average human receives about 2,400 µSv (2.4 mSv) of background radiation in a year, which typically far exceeds the radiation exposure received from an x-ray inspection system in the food industry. This calculates to be around 2,000 µSv (2 mSv) based on an operator working in direct contact, 40 hours per week for 50 weeks of the year. In comparison, pilots and cabin crew, who spend more time at altitude, are exposed to greater levels of cosmic radiation, as there is less of the Earth’s atmosphere to filter it out when flying; with frequent flyers absorbing around 4,400 µSv (4.4 mSv) per year.
X-ray inspection in the food industry
X-ray inspection of food does not cause the food to become radioactive, just as a person does not become radioactive after having a chest x-ray. The U.S. Food and Drug Administration (FDA) report that there are no known adverse effects from eating food, drinking beverages, using medicine, or applying cosmetics that have been irradiated by an x-ray inspection system. They state that a radiation dose typically received by products scanned by x-ray inspection technology is one milliard or less whereas the average dose rate from background radiation is 360 milliard per year.
Put most simply, good food remains good, contaminant-free food.
X-ray systems are safe by design
An x-ray inspection system has three main components: an x-ray generator, a detector and a computer. When switched on, x-ray beams travel through a food product and on to the detector. It is the different levels of x-ray that reach the detector after passing through food that highlight the possible presence of foreign bodies, which on the whole have different densities to the food product.
Unlike radioactive material, an x-ray system can be turned on and off. When switched on, the risk of radiation exposure is controlled through two main protection principles – distance and shielding. In terms of the former, radiation intensity declines rapidly as you move away from the source. Shielding is controlled by the manufacturer of the x-ray system, and it is for this reason that most units are encased in stainless steel. Another factor today is that detectors on modern x-ray systems are highly sensitive, allowing the power of the x-ray source to be reduced.
A number of additional safety features are used as standard, such as tunnel curtains to retain emissions, a safety interlock design, and full integration with the food manufacturer’s production-line safety circuit if required. The manufacture of x-ray inspection systems is subject to regulations such as the U.S. Food and Drug Administration Code of Federal Regulations Title 21 CFR 1020.40 ‘Cabinet X-ray Systems.’ Such regulations ensure that even if a person stands next to a machine every hour of the working day, the equipment is safe to use. Many modern systems are also automated to minimize operator involvement.
Food that is good to eat before being x-rayed remains so afterward. In addition to the scientific evidence, customers of food brands that have already adopted x-ray inspection have detected no change in flavor or texture. Operators working with x-ray inspection systems are protected by equipment design and legislation around it. The technology is vital to detecting foreign bodies that represent a real risk to human health in food products. The conclusion must be that x-ray inspection is a force for improving food safety and quality, not reducing it.
The “How Safe is X-ray Inspection of Food” white paper can be downloaded from the Eagle Product Inspection website: http://www.eaglepi.com/en/knowledge-base/white-papers/how-safe-is-x-ray-inspection-of-food or visit www.eaglepi.com for more information.