FAQs

What types of packaging can AIS inspect?

Pharmaceutical, medical, home and personal care products can be packaged in an unlimited list of packaging types including cartons, boxes, bottles, tubes and sachets. Products can be in multi-packs, elaborately packaged bottles, boxes and gift sets, vacuum packed and security sealed.

Our x-ray inspection systems can be configured to inspect each of these, whether packaged in metal foil and composite materials, glass packaging or even full cases of products.

We can also inspect electronic medical devices and personal care items, food and many other products.

Is x-ray harmful for food?

The detection of physical defects and contaminants using X-ray technology is an important part of quality control for specific food businesses.

European Food Information Council (EUFIC)

At AIS, we use advanced x-ray technology to inspect food for physical contaminants and for quality control.

X-ray inspection of food does not cause it to become radioactive¹. X-ray inspection which delivers a dose of less than 0.5 Gy to food products is permitted under EU Directive 1999/2/EC. The typical dose for an x-ray linescan system, such as at AIS, is less than 0.2 milli-Gy.

Consumers should experience no change in food quality other than improvement by the removal of undesirable contamination; a statement supported by leading brands across the world.

Scientific evidence

A study by the World Health Organisation (WHO) proved that food that has passed through an x-ray inspection system remains safe to eat and loses none of its nutritional value.

• The World Health Organisation (WHO) study in 1997 confirms that food radiation levels up to 10,000 Gy does not affect food safety or nutritional value
• The dose levels used in x-ray inspection are less than one ten millionth of those used in the WHO study
• This level is so low that organic food can be subject to x-ray inspection with no diminution of its organic status

In comparison, the dose level for food irradiation (to destroy bacteria) is much higher.
⁽¹⁾ For further information please read our dedicated FAQs page – “How safe is X-ray Inspection?” – describing the differences between food x-ray inspection and food irradiation.

What can the Micron Scan detect?

Our highest resolution x-ray scanner can detect extraordinarily small contaminants:

• A sieve wire of just 0.2mm in a single item
• A piece of metal just 1.0mm sphere in a multi-pack or case
• Glass fragments down to 1.0mm
• As well as stone, calcified bone and certain rubbers and plastics

AIS provide product safety testing via x-ray inspection, which is restricted to the capabilities of x-ray -detecting foreign materials rather than testing for toxic materials.

Our product inspection service can ensure there are no harmful foreign bodies and broken or missing components that could compromise safety, in either the product or its packaging. This is a service, most often carried out at the end of the manufacturing process, that will also improve product quality and assist you in gaining compliance.

AIS is accredited for ISO 9001 (to operate a Quality Management System), which means we can help manufacturers and suppliers to meet product safety standards including HACCP, TACCP, GFSI & GMP.

Please contact us for a fast and confidential assessment for your particular product and problem.

Find out more about our x-ray capabilities.

What is our Free Sample Inspection?

Our Free Sample Inspection service offers a no obligation evaluation of what is achievable for your product and problem. Simply complete the form here and send a sample of your product for inspection at AIS’ premises.

This initial evaluation is reasonably immediate, confidential and free and we will always provide an honest appraisal of what is possible. All enquiries are treated as 100% confidential.

You can also call us – we can often evaluate the issue on the phone.

What is a GMP inspection?

Good manufacturing practice (GMP) is the minimum standard that a medicines manufacturer must meet in their production processes.” Gov.uk

AIS do not provide “GMP inspections” but our x-ray inspection service will help pharmaceutical manufacturers to meet the consistent quality requirements of GMP.

Pharmaceutical inspection can provide additional assurance for patient safety as well as improve processes and brand integrity, and assist you in gaining compliance.

Please contact us for a fast and confidential assessment for your particular pharmaceutical products.

Can we provide testing to British Standard EN 71?

Our x-ray inspection service does not provide certification to EN 71 but we can guarantee compliance to certain parts of this British Safety Standard, offering an additional guarantee to help you ensure child safety.

Our x-ray machines can quickly and reliably scan for internal or hidden defects within toys and games that may pose a threat to consumer safety:

• sewing needles or metal fragments
• other physical contaminants, down to 1.0mm*
• missing or broken internal components
• damaged packaging

Please contact us for a fast and confidential assessment for your particular toys and problem.

Find out more about our x-ray capabilities.

How soon can we start the inspection process?

We can usually begin tests immediately upon receipt of your product sample and confirm the results of our appraisal the same day (see What is AIS’ Free Sample inspection?’).

The full inspection process would usually commence within 2 to 3 days, under normal circumstances, subject to the logistics of delivering product batches to our premises.

It has been possible to start inspection as quickly as the day after evaluation.

How long does it take to inspect the product?

The inspection time is dependent on the target defect or contaminant, the product and pack size, if it can be inspected in a case or has to be stripped from the case, re-shrunk wrapped etc.

A pallet can be as quick as 5 minutes or as long as two hours.

Request a Free Sample Inspection for AIS to evaluate your product and the likely timescale required for your particular problem.

You can also call us – we can often evaluate the issue on the phone.

How much does our x-ray inspection service cost?

Our x-ray inspection service is generally quoted at a simple per-item fee.

The pricing structure is based on the product inspection time plus any additional services such as shrink wrapping or relabelling. The cost is then converted into a ‘per-item’ (unit or case) price so you know exactly how much the inspection service will be.

The fee per item will be dependent on several factors including:

• The fault or contaminant to be detected (eg. level of difficulty and time required)
• The product size, quantity and value
• Special requirements, urgency or expiry date(s) if applicable

We are confident that you will find our service fast, efficient and cost effective – even for relatively low value products.

Request a Free Sample Inspection for AIS to evaluate your product and problem.

What toys, games and novelty goods do we inspect?

Our comprehensive range of x-ray inspection systems is configurable to many common quality and safety issues in hundreds of children’s toys and games such as soft toys, board games and arts and crafts sets.

We can detect missing or broken parts quickly and accurately and, in most instances, it is not necessary to unpack toys and games to detect a faulty item.

The systems can also be customised to the specific quality issues of children’s clothes and textiles or electronic goods.

What electrical goods can we inspect?

Our comprehensive range of x-ray systems is configurable to a variety of potential problems with electronic goods in both the consumer and industrial sector.

Previous projects have included quality inspection of computer peripherals, medical devices and electronic personal care items.

Please contact us for a fast and confidential assessment for your particular product.

What is the risk of passing food products through an x-ray system?

X-ray inspection which delivers a dose of less than 0.5 Gy to food products is permitted under EU Directive 1999/2/EC.

The dose received by a product passing through an x-ray system is extremely low, typically for an x-ray linescan system it is less than 0.2 milli-Gy.

For more detailed information please visit this European Food Information Council article, or see: “How safe is X-ray Inspection?”

What size of glass contaminant can we detect?

The size of shard or fragment that we can identify is influenced by the thickness and homogeneity of the product being inspected, as well as the type, size and shape of its packaging.

Our highest resolution x-ray scanner (the Micron Scan) offers glass detection down to 1.0mm in certain product and packaging types, yet if the container is made from glass or metal, for example, this may increase to 2.0mm.

We offer a free and confidential assessment to guarantee the highest accuracy for your particular problem.

What packaging types can we inspect for glass contaminants?

Glass detection is possible – to varying resolutions – in loose product, single items and cases or trays of packaged product.

We can inspect almost any packaged product for glass contaminants: food wrapped in foil and composite metals, cans or even a variety of non-consumable products such as toys and electrical goods – often without unpacking the goods.

AIS’ x-ray scanners can detect glass within glass packaging down to 2.0mm. We have inspected glass bottles, jars and elaborately shaped glass containers – common for food and drink products as well as personal care products and pharmaceuticals.

What contaminants and defects can we detect in glass packaging?

Many contaminant types and packaging defects can be identified simultaneously using x-ray technology.

Typical examples include:

• Large glass or metal parts in trays or cases of products – often without unpacking it
• Small glass, stone or metal fragments in single containers
• Product agglomerates
• Fill level inspection
• Broken bottle necks and other container faults
• Glass contaminants in glass packaging down to 2.0mm

What foil and metal-based packaging types can we inspect?

Quality checks and detection of metal and other physical contaminants is possible – to varying resolutions – in almost any packaging.

We can inspect most common metal and foil composite packaging types in the food and drink and pharmaceuticals industries:

• Sachets, usually made from laminated plastic and aluminium
• Semi-rigid packaging, typically single-use aluminium containers to cook or reheat food
• Plastic and foil trays, including multi-component trays

Custom metal, foil and composite packaging can also be inspected including non-consumables such as toys and electrical goods.

The type of contamination or quality issue will affect the resolution that our x-ray scanners can achieve. Please request a free and confidential assessment for your particular packaging and problem.

What factors can affect the size of physical contaminant detectable within packaging?

The size that we can identify is influenced by several factors:

• The thickness and homogeneity of the food or product within the packaging
• The density and position of the physical contaminant
• The type, size and shape of the packaging
• Whether inspecting single items or whole cases

We offer a reasonably immediate appraisal of what can be achieved with your product or particular container. Simply send a sample of your product for inspection, or call us – we can often evaluate the issue on the phone.

What size of physical contaminant can be detected in foil and composite packaging?

Our highest resolution x-ray scanner (the Micron Scan) can detect a sieve wire of just 0.4mm in a single item or a piece of metal just 1.0mm sphere in a whole case. It can also detect glass fragments down to 1.0mm as well as stone, calcified bone and certain rubbers and plastics.

We offer a free and confidential assessment to guarantee the highest accuracy for your particular problem.

What contaminants and defects can be detected in foil or metal-based packaging?

Glass, metal and many non-metallic substances can be identified within food packaging using x-ray technology, even if the product is frozen.

We offer simultaneous inspection for common manufacturing and packaging faults.

Typical examples include:

• Large metal or dense fragments in whole case inspection
• Small metal, glass, stone, or bone fragment in individual packs
• Under-fill in cases and individual packs
• Missing components in multi-component trays
• Electrical cable covering and other dense plastics and rubber

What size of contaminant can we detect within cans?

The size that we can identify is influenced by the thickness and homogeneity of the food or product within the can, as well as the contaminants’ density and position.

Our highest resolution x-ray scanner (the Micron Scan) can detect a sieve wire of just 0.1mm in a single can or a metal contaminant of 1.0mm sphere when inspecting a case. It can detect glass fragments down to 1.0mm as well as stone, calcified bone and certain rubbers and plastics.

We offer a free and confidential assessment to guarantee the highest accuracy for your particular problem.

What contaminants and defects can be detected in canned food?

Many contaminant types and quality issues can be identified simultaneously using x-ray technology.

Typical examples include:

• Stone, glass, metal and bone detection
• In-case inspection for filler nozzles and metal fragments down to 1.0mm sphere
• Inspection of single cans for smaller contaminants down to 0.4mm
• Damaged cans and manufacturing faults
• Under-fill and low-sauce fill detection

What size of physical contaminant can be detected in bakery and confectionery?

The size that we can identify is influenced by the thickness and homogeneity of the product, its packaging and size and the contaminants’ density and position within the food or pack.

Our highest resolution x-ray scanner (the Micron Scan) can detect a sieve wire of just 0.2mm in a single item or a piece of metal just 1.0mm sphere in a multi-pack or case. It can also detect glass fragments down to 1.0mm as well as stone, calcified bone and certain rubbers and plastics.

We offer a free and confidential assessment to guarantee the highest accuracy for your particular problem.

What contaminants and defects can be detected in baked goods?

Our x-ray technology can quickly and simultaneously identify many contaminant types and quality concerns in bakery and confectionery, in many forms of packaging – even if the product is frozen.

Typical examples of contaminants and defects which can be detected in baked goods include:

• Contaminants inside packaging or within the food itself
• Mineral stones, bone and glass fragments
• Metal, certain rubbers and plastics – common machinery faults
• The smallest stainless steel sieve wire fragments down to 0.2mm diameter
• Product agglomerate in coated cereal products
• Under-filled pies and missing components in multi-packs

What contaminants can be detected in meat?

Glass, metal and many non-metallic substances can be identified during x-ray inspection of meat and meat products, even if the product is frozen.

Typical examples include calcified bone and fragments of stone, metal and glass, dependent on the product and size of unit or carton.

What meat products do we inspect?

AIS offer x-ray food inspection of meat, often combined with meat fat analysis, for a variety of meat cuts and processed meat products including beef, pork, lamb, chicken and venison.

We typically inspect cartons of frozen meat weighing between 25kg and 27kg.

We offer a free and confidential assessment to guarantee the highest accuracy for your particular problem.

How reliable are the x-ray inspection techniques?

AIS has many years’ of experience in providing specialist x-ray inspection services. We are ISO accredited to help you achieve compliance for potential recall incidents, HACCP and TACCP.

Over 95% of our business is repeat business from long term clients, mainly within the food and pharmaceutical sectors.

Reliability can differ due to many factors. We will always give a clear and honest appraisal of what is achievable and be prepared to demonstrate that to you at any time.

Request a Free Sample Inspection for AIS to evaluate your product and problem.

What methods are used to measure Chemical Lean?

Chemical Lean, a key factor in assessing food quality, is a comparison of the amount of lean meat vs fat in meat or meat products, traditionally measured from a single sample.

Frequently used methods to measure Chemical Lean include the Soxhlet method and NIR technology, yet neither procedure is as fast and accurate as AIS’ fat analysis service.

Our machines use Dual Energy X-Ray Absorptiometry (DEXA) which can quickly measure the total fat content of a larger sample of meat, to help UK meat producers and processors to cost-efficiently gain value and achieve compliance.

How long does it take to inspect meat products?

Meat inspection can take anywhere from 5 minutes to 15 minutes per pallet, depending on the product size and inspection requirements.

Contact us for a fast, free and confidential assessment of the required timescale for your particular problem.

Can we provide solely Fat Analysis or solely contaminant detection?

We will be happy to provide either Fat Analysis or contamination detection for meat products as separate service. Please contact us for a Free Sample Inspection and quotation.

Does AIS have frozen or chilled facilities?

We regularly provide a safe, fast and effective inspection service for frozen and chilled foods, however we do not offer freezers or refrigerated storage on the premises.

We have multiple hook up points and a large secure yard which can accommodate up to 10 refrigerated trailers.

Working directly from the trailers, each pallet is removed it is temperature monitored throughout the inspection process and then immediately returned to the trailer (or a spare trailer which is then replaced on the next load). A full trailer can usually be inspected and turned round in a few hours.

We regularly inspect chilled and frozen food for well-known brands and this has proven to be the most efficient method.

 What other types of clothing quality inspection are available?

Big brand fashion labels will use a plethora of additional Quality Control tools and visual inspection methods to a strict set of guidelines, to ensure their brand reputation is upheld:

• fabric quality and conformance
• garment shape and size
• print and pattern alignment
• fastenings, zippers and accessories
• labelling and packaging

However this level of assessment may be out of the reach of smaller brands and UK imports, who may be looking for a fast and efficient quality inspection service to help ensure that garments with a critical defect do not reach consumers.

What clothing quality checks can we provide?

Clothing quality inspection can be carried out at various stages of the manufacturing process: pre-production, in-line and post-production. At AIS, we usually provide an inspection service at the end of the manufacturing process, and often for brands imported to the UK.

Our x-ray inspection equipment can quickly and reliably scan for internal or hidden defects within clothes and seams that may pose a threat to consumer safety:

• sewing needles or metal fragments
• missing or broken zippers and fastenings
• missing or broken accessories
• missing labels
• poor quality stitching
• damaged packaging

Please contact us for a fast and confidential assessment for your particular items and problem.

 Does AIS have ISO9001 approval?

Yes we do, in fact we were the first specialist x-ray recovery provider in Europe to obtain the approval to operate a Quality Management System which complies with the requirements of ISO 9001.

Read more about how AIS can help you achieve the governmental and retailer requirements of contamination and recall incidents.

HACCP is a way of managing food safety hazards. Food safety management procedures should be based on HACCP principles … what could go wrong and what risks there are to food safety” Food Standards Agency

HACCP is a food safety management system designed to prevent contamination during food production processes, rather than a finished product inspection procedure.

AIS can help you achieve HACCP and the governmental and retailer requirements of contamination and recall incidents. We can also provide quality and safety assurance when a Critical Control Point (CCP) has failed.

Contact us to find out more.

Threat Assessment and Critical Control Point (TACCP) helps food producers identify weak points in their supply chain and processing activities that may be vulnerable to fraud. It then helps the business minimise the chances of such an attack.” Campden BRI

If your business is the unfortunate victim of a threat or attack, AIS is equipped to assist you with product recovery and safety testing. In the event of an incident (subject to it being a foreign body we can detect) we will be able to quickly and confidentially confirm whether your product is safe to go back into the distribution chain.

Read more in the TACCP guide, sponsored by Defra and the FSA: PAS 96:2017 (Guide to protecting and defending food and drink from deliberate attack)

 Does AIS provide transport?

We do not supply transport as we cannot match the rates and logistic resources of our clients.

 Does AIS guarantee confidentiality?

Yes we do.

We will never share any information regarding our clients or our projects, whether current or historical, regarding an enquiry, initial evaluation or continued inspection services.

Furthermore, information gathered via our website is handled in complete confidence; all traffic statistics generated are anonymous and we store no personal details.

Please read our Privacy Policy.

Is AIS on social media?

“You won’t find us on Facebook, Twitter or YouTube”.

We maintain a professional company profile on LinkedIn where we share industry and technology news and information that may assist businesses with compliance or potential recall incidents.

We will never “tag” or publicly identify our clients or contacts on social media, or any other digital marketing, without their explicit consent.

Does AIS work 24 hours?

We have done, but generally we find it more efficient and manageable to extend the working day and bring into operation some of the additional equipment we always have available.

Are we open to audit of both our premises and procedures?

Absolutely, we are regularly audited by most of our customers and their clients.

 Can you be present whilst your product is being inspected?

You are more than welcome to be present, from the first day of the inspection process until the last.

If you wish to meet the team or visit our premises, please get in touch and we will be happy to arrange this for you.

We aim to answer all your questions efficiently and succinctly without bombarding you with technical jargon. If, however, you wish to have a full technical briefing on the inspection equipment and techniques employed we are more than happy to provide this.

Does AIS have a confidentiality agreement?

Yes, we have our standard bi-lateral non-disclosure agreement and will consider any reasonable confidentiality agreement from a customer.

Does AIS have written procedures?

Yes, these are our “Standard Operating Procedures”. We will however modify and add to our SOPs to meet the individual requirements of your specific product.

Does AIS have an environmental policy?

We aim to be a sustainable business and protect the environment where possible:

• Our service can help manufacturers to avoid waste by destroying only contaminated or faulty goods while safe products are released back into distribution
• All packaging material removed during the inspection process is sent to be recycled including shrink wrap, cartons, glass packaging and cans
• We try to source sustainable suppliers including a predominantly biomass-fuelled electricity supplier

Can I hire x-ray inspection equipment?

Yes, some of our customisable x-ray inspection systems and metal detectors are available to rent at your premises. These can be hired, subject to availability, on flexible contract periods – usually for an immediate or short term requirement.

Find out more about X-Ray Inspection Equipment Hire.

How do AIS’ new scanners compare with on-line equipment?

The main differentiator is the resolution achieved with the use of advanced linear sensors:

Standard x-ray inspection equipment for the food industry typically records 140,000 data points in a 15 x 15cm product.

AIS X-Ray Micron Scan achieves a resolution of 9,000,000 data points in the same sample. This additional resolution ensures detection of incredibly small foreign bodies and is much less sensitive to the orientation and location of the contaminant within the product.

AIS X-Ray Ultra Scan offers a resolution of 600,000 data points in the same sample of 15 x 15cm (achieving detection of contaminants as small as 0.4mm metal / 1.2 mm non-metallic substances).

Can the new AIS X-Ray scanners operate on-line or near- line?

Ultra-high resolution sensors cannot match the high speeds used on modern production lines.

The AIS X-Ray Micron Scan is designed to operate off-line and be operated by AIS’ expert staff to achieve its optimum accuracy.

The AIS X-Ray Ultra Scan can be deployed at near-line and off-line locations.

How are the x-ray inspection machines set up?

All systems consist of a conveyor cabinet and x-ray generator plus high powered PC and software for x-ray detection and image processing.

To take full advantage of the higher resolution, the image processing hardware and software must be able to handle the data rate that the detectors produce. The hardware and software within the Micron Scan and Ultra Scan are optimised to handle these high data rates.

What are the Health & Safety requirements for hiring our x-ray inspection machine?

At our own premises, AIS have ISO accreditation to meet food and product safety standards including HACCP, TACCP, GFSI & GMP. We can therefore assist you in meeting health & safety and regulatory requirements and enabling your users to operate the hired equipment safely and correctly.

What are x-rays?

X-rays are electromagnetic radiation, part of a single continuum known as the electromagnetic spectrum, this is arranged according to frequency and wavelength, and runs from radio waves at one end (which have a long wavelength) to gamma rays at the other (which have a short wavelength).

The short wavelength of x-rays enables them to pass through materials that are opaque to visible light, however they do not pass through all materials with the same ease. The transparency of a material to x-rays is broadly related to its density – the denser the material, the fewer x-rays that pass through. Hidden contaminants and other dense internal structures, including foreign bodies like glass, bone and metal, show up because they absorb more x-rays than the surrounding product.

The principles of x-ray inspection

In simple terms, an x-ray system uses an x-ray generator to project a beam of low- energy x-rays onto a linear x-ray sensor or an x-ray imaging intensifier.

The system is typically configured with the x-ray generator above the conveyor, which is used to transport the product through the system and the x-ray sensor positioned under the conveyor which collects and converts the x-ray “shadow graph” signals into a visible image.

The x-ray shadow graph is generated as a result of the different attenuating properties to the product under inspection. For instance a fragment of glass in a pack of cheese has a higher attenuation (adsorption) than the cheese in which it is embedded therefore as that section of the pack is inspected the area of glass generates a “shadow” or lower beam intensity that the detector can record and display.

It is by this very simple principle that all x-ray systems operate.

In food products the contaminant generally has higher absorption and therefore generally displays as darker than the background image, yet it is still possible to detect material that has a lower absorption than the background. This allows the detection of voiding in filled packs and the detection of missing components in multiple unit packs.

The same shadow attenuation principles apply for the inspection of pharmaceuticals, broken tablets, missing leaflets etc. and across a whole range of industries and quality applications that are beyond the scope of this brief introduction.

X-ray image generating detectors

There are numerous types of x-ray image generating devices but broadly they fall into two categories:

Line array sensors

A line sensor, also often referred to as a linear array, photo-diode array or line scan detector. As its name implies it is a line of x-ray sensitive detectors which is positioned under the conveyor and across it at 90 deg to the direction of travel of the product. It relies on the motion of the conveyor to generate the image in the travel direction and is the most commonly used method in automated systems.

The advantage of these detectors is that they produce a high contrast low, noise image and operate over a wide energy range. The disadvantage is that as they are made up of a single line of individual sensing elements the spacial resolution becomes a function of the sensor element size.

In security applications such as baggage screening the typical size is 1.6 x1.6mm, in food and industrial inspection, typically 0.8 x0.8mm , 0.4 x 0.4mm and in some cases 0.2 x 0.2mm. There are higher resolution sensors than this but it is unusual to need to deploy them in most applications. However AIS do use much higher resolution sensors for recovery applications.

Area sensors

These can either be image intensifiers of flat panel arrays. In fully automated systems these sensors are unlikely to outperform the line sensors. They were developed for and are generally used in the medical sector – for heart procedures and as a replacement for x-ray film.

The main advantage they have is that a full frame image is generated which is not dependent of movement of a conveyor; in fact movement can be detrimental to the image quality if it is not properly controlled. The other advantage of the image intensifier is that it is a very high gain device with high spatial resolution but at the cost of significant signal noise.

In conclusion both techniques have their advantages and at AIS you will always have access to the most appropriate x-ray inspection system for your requirement.

 How safe is x-ray inspection of food?

Food that has undergone x-ray inspection remains safe to eat and is indistinguishable in every respect from food that hasn’t been x-rayed. Leading food manufacturers across the world rely on x-ray technology for detection of physical contaminants and for quality control.

Discover more about the facts:

• Scientific evidence (by WHO) states that food radiation levels up to 10,000 Gy does not affect food safety or nutritional value
• EU Directive 1999/2/EC permits x-ray inspection which delivers a dose of less than 0.5 Gy to food products
• The typical dose of radiation for an x-ray linescan system, such as at AIS, is less than 0.2 milli-Gy (one ten millionth of those used in the WHO study)
• Organic food retains its organic status after x-ray inspection
• The irradiation dose that would be required to destroy bacteria in food is much higher than the x-ray inspection dose

X-ray Radiation Vs. Radioactivity

What is Radioactivity / Radiation?

X-rays do not pass through all materials with the same ease; the denser the material, the fewer x-rays can pass through – this affects the quality of the x-ray image and capabilities of x-ray inspection. Hidden contaminants, like glass and metal, show up under x-ray inspection because they are denser, and therefore attenuate more x-rays than the surrounding food.

X-ray inspection systems should not be associated with radioactive materials such as uranium. Radioactive materials are physical sources of radiation. They emit radiation in the form of alpha particles, beta particles, and gamma rays– and they do it continuously, which is why they cannot be switched off. The only way to contain radiation from a radioactive material is to encase it in a substance that absorbs radiation.

X-rays used for inspection are different. Like light from a bulb, they can be turned on and off at will. Switch off the electricity supply to the x-ray system, and the flow of x-rays ceases instantaneously.

Radiation in Everyday Life

X-rays are just one of several naturally occurring sources of radiation. The combined effect of all these sources is known as background radiation – and humans have been exposed to it since the beginning of time.

The modern daily dosage received by a typical person is higher than previous generations due to the radiation used in medical science, contributing an increase in background radiation received of about 18%. That might sound like big but the overall levels are so small that the increase is negligible.

The chart below shows the four major sources of radiation that add up to the background radiation received by a typical person.

Putting Radiation Doses into Context*

From the point of view of occupational exposure, the accrued radiation dose is the most important measure. Occupational exposure limits are given in terms of the permitted maximum dose. The SI unit of radiation dose is the sievert (Sv). As occupational exposure levels are normally low, smaller units – millisievert (mSv: a thousandth of a sievert) or microsievert (μSv: a millionth of a sievert) – are more commonly used. The radiation dose rate measures the rate at which radiation is absorbed over time. This is expressed in μSv/h (Dose Rate = Dose (μSv) ÷ Time (hours)).

For the average human, natural background radiation contributes about 2,400 μSv (2.4 mSv) of radiation in a year from natural sources. This typically far exceeds the radiation exposure received from an x-ray inspection system in industry. The typical maximum dose rate immediately adjacent to an x-ray inspection system is <1 μSv (0.001 mSv) per hour which means an operator would receive 2,000 μSv (2 mSv) per year when working 50 weeks a year and 40 hours each week in direct contact with an x-ray system.

Naturally occurring radiation comes from outer space. Our daily dose is small because the atmosphere filters most of it out. The filtering effect declines with altitude so those who fly absorb more x-rays than those who stay on the ground.

A frequent flyer, for example, absorbs around 8% more radiation 200 μSv (0.2 mSv) than a non-flyer. The frequent flyer’s typical annual dose is about 2,600 μSv (2.6 mSv) a year. Pilots and cabin crew absorb more still: about 4,400 μSv (4.4 mSv) a year, depending on routes flown and total flying time. Their annual dose of radiation is typically greater than workers at a nuclear plant – and almost twice as high as those who spend their lives at ground level. Even so, the frequent flyer’s additional dose of radiation is extraordinarily low.

X-ray Inspection Vs. Food Irradiation

Although the effect of x-ray inspecting a road wheel or a suitcase is of little concern, there is naturally reason to be cautious when inspecting items which may be ingested such as food or pharmaceutical products.

Food processors use x-rays in 2 ways:

1. to inspect food for contaminants or quality control, and
2. to irradiate food (a process that destroys bacteria)

The technologies have one similarity – both processes involve radiation – but that is where the similarity ends; dose levels equivalent to several orders of magnitude separate food irradiation from food inspection.

The facts about X-ray Inspection

X-ray inspection of food, pharmaceuticals or any other product does not cause it to become radioactive, just as a person does not become radioactive after having a chest x-ray.

There is scientific evidence to show that x-rays do not harm food. A 1997 study by the World Health Organisation (WHO) confirmed that food radiation levels up to 10,000 Gy does not affect food safety or nutritional value. That means the food was subject to radiation doses around ten million times as great as those used in x-ray inspection. It proved that the food remains safe to eat and that it loses none of its nutritional value. This view is supported by the experience of leading brands across the world who have found that consumers experience no change in the quality other than the improvement by the removal of undesirable contamination.

The dose levels used in x-ray inspection are less than one ten millionth of those used in the WHO study. Food that passes through an x-ray inspection system spends about 250 milliseconds in the x-ray beam and during that short time it receives a radiation dose of around 200 μGy (0.2 mGy). The levels are so low that organic food can be subject to x-ray inspection with no diminution of its organic status.

The facts about Food Irradiation

In comparison to x-ray inspection the dose levels for food irradiation are much higher and range from 500 Gy up to 10,000 Gy in approved protocols for food items. (Source: Radiation Threats and Your Safety, Armin Ansari, 2010, page 311)

Whichever way you look at it, food that has passed through an x-ray inspection system is as good and tasty to eat as it was before it was scanned. There are no measurable changes to flavours, textures, or nutritional values: food that has been x-rayed is indistinguishable in every respect from food that hasn’t.

Please also read this article, ‘X-rays in food inspection‘, by the European Food Information Council (EUFIC).