Food Safety Hazards

Physical Contamination in Food: Glass, Metal, Plastic & Prevention

Preventing Physical Contamination in Food Businesses

Quick answer

Physical contamination occurs when a foreign body enters food at any stage from production to service. It is one of the three HACCP hazard categories and one of the most common reasons for customer complaints, product recalls, and enforcement action in the UK food industry. Foreign bodies can cause injury (broken teeth, cuts to the mouth or throat, choking) and even where no injury occurs, finding glass, metal, plastic, hair, or insects in food destroys customer confidence and can lead to negative reviews, legal claims, and reputational damage. For food businesses, prevention requires a systematic approach covering your premises, equipment, people, and processes.

Physical contamination is one of the most common causes of food complaints and can result in customer injury and legal action.
Glass, metal, and plastic are the highest-risk physical contaminants in most food businesses.
Prevention requires systematic controls: glass policy, equipment maintenance, staff policies, pest control, and ingredient inspection.

Key takeaways

Physical contamination is one of the most common causes of food complaints and can result in customer injury and legal action.

Glass, metal, and plastic are the highest-risk physical contaminants in most food businesses.

Prevention requires systematic controls: glass policy, equipment maintenance, staff policies, pest control, and ingredient inspection.

Investigate every foreign body complaint to root cause and document your findings and corrective actions.

Blue detectable plasters should be standard in every food business to address the lost-plaster risk.

Common Sources of Physical Contamination

The most frequently reported physical contaminants in UK food businesses include: glass (from broken bottles, jars, light fittings, or thermometer casings), metal (from worn equipment, loose screws, broken knife tips, wire wool, and staples from packaging), plastic (from packaging materials, broken utensils, disposable gloves, cable ties, and equipment components), wood (from pallets, wooden utensils, toothpicks, and splinters from worn chopping boards), hair (from food handlers who do not wear adequate head covering), insects and pest debris (flies, cockroach fragments, rodent droppings), bone fragments (from butchery or inadequate trimming), stones and grit (from unwashed vegetables, pulses, and grains), and personal items (jewellery, plasters, pen lids, buttons). Each of these has specific prevention measures. Your hazard analysis should identify which are most relevant to your operation based on your ingredients, equipment, and processes.

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Prevention Controls

Glass management: implement a glass and brittle materials policy. Use shatterproof containers wherever possible. Cover light fittings with protective sleeves. If glass breaks, clear the area, dispose of all exposed food, clean thoroughly, and document the incident. Metal detection: where high-risk or high-volume production warrants it, use metal detectors on production lines. In smaller kitchens, regularly inspect equipment for wear, loose parts, and damage. Replace worn sieve mesh, colander mesh, and whisk wires before they break. Plastic and packaging: remove all outer packaging before bringing ingredients into the preparation area. Use blue plasters (which are both visually conspicuous and detectable by metal detectors if they contain a metal strip) and ensure staff report any lost plasters immediately. Personal contamination: enforce a strict policy on jewellery (wedding band only, no earrings, bracelets, or watches), hair nets or hats, and no personal items in food preparation areas. Pest control: maintain a professional pest control contract with regular inspections and proactive measures.

Responding to Foreign Body Complaints

When a customer reports finding a foreign body in their food, take it seriously regardless of how trivial it may seem. Retrieve the item if possible and preserve it (photograph it, place it in a sealed bag or container). Record the details: what the item is, which dish it was found in, the date and time, and the customer details. Apologise, replace the meal, and consider what further gesture is appropriate. Investigate the root cause. Where did the item come from? Trace it back through your process: was it present in the raw ingredient, introduced during preparation, or from equipment or the environment? Check the batch of ingredients, inspect the relevant equipment, and review the cleaning records. Document your investigation and any corrective action. If the foreign body could cause injury (glass, metal, bone) or if the customer has been injured, the incident may be reportable to Environmental Health. Multiple foreign body complaints of the same type indicate a systemic problem that needs urgent attention.

Integrating Physical Hazards into Your HACCP Plan

Your hazard analysis should identify physical contamination risks at each process step. At receiving, check packaging for damage that could introduce foreign bodies. During storage, maintain pest control and keep food covered. At preparation, inspect raw ingredients (particularly leafy vegetables, pulses, and flour), check equipment for wear, and enforce the jewellery and hair covering policy. Most food businesses control physical hazards through prerequisite programmes rather than designating them as CCPs, since the controls (pest control, glass policy, equipment maintenance, staff policy) are ongoing programmes rather than measurable critical limits at specific points. However, if your operation includes a sieving or metal detection step that specifically targets physical hazards, that may qualify as a CCP with a measurable critical limit (e.g. all product passes through a sieve with a maximum aperture size).

What to do next

Implement a glass and brittle materials policy

Audit your premises for glass items (bottles, thermometers, light fittings, mirrors) and replace with shatterproof alternatives where possible. Document a procedure for glass breakage: clear area, dispose of exposed food, clean, record.

Schedule regular equipment inspections

Create a monthly checklist to inspect all food preparation equipment for wear, loose parts, cracked plastic components, and damaged mesh or wire. Replace before failure occurs.

Enforce a strict personal items policy

Display clear signage in changing areas: no jewellery except plain wedding bands, hair nets or hats required, blue plasters for all cuts, and no personal items (phones, pens, lighters) in food preparation areas.

Common mistakes to avoid

Mistake

Dismissing a foreign body complaint as a one-off

Instead

Every complaint deserves investigation. A single finding may indicate a systemic issue (worn equipment, inadequate pest control, poor ingredient checking) that will produce repeat incidents if not addressed.

Mistake

Using standard skin-coloured plasters in the kitchen

Instead

Skin-coloured plasters are hard to spot if they fall into food. Blue detectable plasters are visually obvious and many contain a metal strip for detection. They should be the only plasters used in food areas.

Frequently asked questions

What should I do if glass breaks near food?

Stop all work in the area immediately. Remove and discard all exposed food, including anything in open containers or uncovered dishes within the breakage zone. Carefully clean the area, checking for fragments in drains, on shelves, and in any equipment. Do not use a brush for fine fragments; use damp paper towels to pick up small pieces. Document the breakage, the food discarded, and the cleaning action taken.

Do I need a metal detector in my kitchen?

For most restaurants, cafes, and small food businesses, a metal detector is not necessary. Physical hazard controls through good practices (equipment maintenance, ingredient inspection, staff policies) are sufficient. Metal detectors are more common in food manufacturing and processing environments where high volumes pass through a production line. Your HACCP plan should assess whether the risk justifies the investment based on your operation.

How do I prevent contamination from packaging materials?

Remove outer packaging (cardboard, plastic film, cable ties, staples) before bringing ingredients into the preparation area. Open inner packaging carefully with scissors rather than tearing, which can introduce plastic fragments. Check the inside of containers and cans before emptying their contents. Train staff to be aware that packaging is a contamination source.

Food Safety Hazards