Identifying physical hazards and control measures

Identifying physical hazards and control measures

  • Raw materials

The variable nature of raw material quality may be a significant problem in food processing. Raw materials can be a major source of extraneous matter and food manufacturers use a range of cleaning, sorting and grading operations to separate out of the offending material. In the manufacturers of frozen peas for example, stones, metal screws, cigarette ends, stalks, sticks, caterpillars and dirt often accompany the vined peas as they arrive at the factory.

control measures should include specifications to detail maximum permissible levels of contamination in the incoming of raw materials. By agreeing specifications with all suppliers and monitoring and evaluating the supplier performance in meeting the specifications, the company has effective tool in minimising the risk post by extraneous matter.

Before using raw materials, cleaning or washing and inspection may need to be carried out. most physical contamination has to be removed by food handlers as the vegetables pass along illuminated inspection belt.

Liquids used in food production should be filtered and powdered sieved. Filters, screens and sieves should be as fine as possible and must be cleaned and checked regularly. Worn equipment must be replaced. Wooden-framed sieves are usually unacceptable.

  • Packing materials

Packaging may be a source of extraneous matter in the form of warehouse and transport dirt/dust, wood from the pallets, paper and polythene strips from over wraps and a variety of insects and even rodents. Containers (cans, jars, bottles, and plastic pots) may be used directly for filling minimal cleaning and any rogue material in the container ( metal splinters, glass, dirt, insects ect) may end up in the final product.

 Staples,, cardboard, string, fibres, cloths, rubber, plastic and polythene

Food may be delivered in various containers including paper sacks, cardboard boxes and polythene bags. Particular care is necessary when emptying containers to avoid contamination of food. As far as practicable, all unpacking and packing should be carried out in areas separate from food production or preparation. If open food is exposed to rick of contamination.

Sting removed from hessian sacks and ties removed from bags should immediately be placed in suitable containers provided specificity for the the purpose. As an extra precaution, coloured string may be specified to aid detection should it end up in the product. Paper sacks should be cut open, although care must be exercised to ensure pieces of paper do not finish up in the food. It is preferable for raw materials to be emptied into suitable lidded containers and not dispensed direct from paper sacks.


Particular care is needed to ensure that staples, which tend to fly considerable distances when boxes are prised open, do not contaminate food. Suppliers should be requested to use adhesive tape to fasten boxes, instead of staples. Many products are delivered in black polythene bags and small pieces of polythene often end up in the product.

Effective measures in terms of good hygiene practice should be adopted within the HACCP scheme to minimise the risk of contamination. An example would be the use of secondary packing which is removed prior o primary packaging material entering a high-risk area.

  • The building, Installations and equipment 

Wood splinters

As far as possible the use of wood, especially soft wood, should be eliminated from food production areas. Wooden containers used for transporting raw materials should be phased out. Pallets should not be double stacked over open food.

Bolts, nuts and pieces of metal

As far as practicable nuts should be self-locking. Bolts, nuts and screws should be non-corroding and positioned to ensure that, should they fall of equipment, they do not drop in to food.

Flaking paint or rust

Ceiling structure, pipes or equipment should be non-flaking and rust-free. This is especially important when sure fixtures are positioned directly above open products. In some older factories this problem is very difficult to over come and consequently additional protection is necessary, for example, enclosed system for conveying food and empty containers such as cans. New food premises should be designed so that fixtures, ducts and pipes are not suspended over working areas or food if the product is exposed to risk of contamination, for example, from condensation. 

Grease and oil

Wherever necessary, food-grade and lubricants should be used. It is important that engineers use the minimum amount necessary to lubricants moving parts and that grease is not left on the machine. Careful control will ensure the absence of complaints relating to grease in foods. It is preferable for motors not to be positioned above open food. When this occurs, suitable non-corroding, cleanable drip-trays should be fixed underneath to catch oil spoilage.


 As far as practicable the use of ordinary glass should be minimised in food rooms. Perspex or wired glass windows should be used. Protective sleeves or diffuses should be fitted to fluorescent tubes in any rooms where breakage would expose food to risk or contamination. Dials and gauges on equipment should be unbreakable. Mirrors and glass thermometers should not be used. Unauthorised glass containers or equipment should not be brought into food rooms. All food businesses should have a glass policy especially to deal with glass breakages. When replacing or cleaning fluorescent tubes or diffuses, food and containers should be removed or protected so there is no risk of contamination.  

 In the event of breakage, food preparation should be stopped. All potentially contaminated food should be discarded. Food containers should be checked for broken glass and cleaned. All broken glass should be swept up and disposed of in a safe manor. The brush used should be discarded as it is likely to contain broken glass. The area should be fully cleaned and inspected before food preparation starts again. Staff will require appropriate instruction and/or training to ensure they respond correctly to breakages.

In factories, optical scanners, filters, sieves, x-ray machines and air separation systems may be used to detect and/or remove glass from food. In the event of products being contaminated with glass it may be necessary to recall the food and notify the environmental health department. Breakages when filling glass jars or bottles are always likely and particular care is needed to ensure containers adjacent to fillers when breakage occurs and discarded. Furthermore, a suitable system, e.g. inverting and washing or blasting with air, is necessary to minimise the risk of broken glass being present in a container just prior to filling.



Notices used for warnings, advice or instructions should be properly fixed and permanent. Sheets of paper sellotaped to equipment or close to open food are unacceptable. Recipe instructions should be enclosed in sealed polythene  bags. Notice boards should be kept out of areas where open food is handled and should be covered in perspex or similar sheeting. 

Food handlers

Contaminants, which originate for personnel, include earrings, hair, fingernails, buttons, combs and pen tops. Protective clothing, including head covering, must be of a suitable type and worn correctly. The personal hygiene of food handlers must be beyond reproach, and earrings and jewellery, other than wedding rings, should not be worn. Pencils, pens and pieces of chalk must not be used in situations which expose food to risk of contamination, for example, near filling hoppers and mixing vessels. 

Sweet papers, cigarette ends and matches are common contaminates and staff should not eat sweets, chew gum or smoke in food rooms. Regular training and reinforcement, such as posters, should be used together with strict supervision and enforcement or company rules.

Cleaning activities

Care must be taken during cleaning and all staff involved should be trained to ensure they do not expose products to risk contamination by using worn equipment, especially brushes which are likely to lose their bristles, or by using inappropriate methods such as high pressure spraying during the production of open food. Particular care must be exercised when using paper towels and cloths to ensure small pieces of paper or cloth do not end up in the product.

Maintenance operatives/tradesmen

Engineers must be trained/briefed to take extra care when working with food equipment to ensure that do not leave loose nuts, swarf and pieces of wire in food rooms on completion of maintenance. Written instructions may be useful. Temporary repairs with string should be avoided. It is good practice for managers to check areas where engineers or contractors have been working before food handlers commences.

During production, areas which are being decorated or where repair or maintenance work is being carried out must be suitably segregated by screens such as, heavy-duty polythene , to avoid exposing product of risk of contamination. Workers should be closely supervised during maintenance activates. Maintenance workers should not wear soiled overalls and suitable protective clothing may be provided by the food business. They should not stand on or climb over over machinery or open food if there is the slightest risk of introducing contamination. They should not smoke or eat sweets and should observe good hygiene practise. If necessary, all food and food containers should be removed or protected with clean polythene sheeting. The use of ladders over open food or hoppers can result in dirt falling of shoes or rungs and ending up in the final product. After all the work has been completed all tools,  screws, swalf, grease ect. must be removed and the area cleaned and, if necessary, disinfected before use. When ever possible, equipment should be removed from areas for repairs.

Add photo of a working repairing kitchen equipment

Pest and pest control

Rodents, rodent hairs and droppings may be brought into food premises with the raw materials or introduced during the preparation or storing of food in infested premises.  Food showing evidence of rodent contamination is unfit and should be rejected.

Insects, larvae and eggs may also be be present in raw materials, although some may find there way in to foods via openings. Several type of insect multiply rapidly and infestations can soon spread through out food premises. Infested food should be discarded and appropriate control measures introduced. A reputable pest control contractor, experienced working with food businesses, should be employed to lay rodent bait or traps and control pest infestations should they arise.

Bad pest control is likely to result in food contamination. For example, electronic fly killers poisoned above open food, work surfaces or containers will probably result in dead insects in the food, as will the use of insecticides to destroy flying insects, for example, sprays,  in the presence of open food.

Cleaners and other staff must be instructed not to touch bait boxes, unless authorised to do so, and never to put bait boxes on shelves above open products whilst cleaning is being undertaken.


Customer contamination

Customers may contaminate food which is not adequately protected, especially when they serve themselves. Handling and sneezing over food is probable and inquisitive customers may break seals to examine to content of the jars and tubs. Furthermore, malicious tampering of products i  supermarkets continues to pose a threat to manufacturers and retailers. Finally, contamination of the product may occur in the customers home and this should be considered when investigating a complaint.

All reasonable precautions and all due diligence

A food company facing a prosecution as a result of selling a contaminated product ill need to demonstrate that they have installed and used a effective, documented detection and rejection system, which is checked regularly,  if they are to successfully use the due-diligence defence provided in food safety legislation. It will be up to the courts to decide what is ‘reasonable’ having regard to good trade practice, industry hygiene guides and the risk and consequences in relation to cost.

Foreign body detection and removal in food manufacturing

No system can guarantee to remove every contaminant and the effectiveness of a particular machine or system will depend on the type of foreign body, the initial level of contamination and the maintenance of the equipment. The performance of most machines will deteriorate with age and use and constant testing is essential. There are many contaminant detection and removal systems available including:

  • metal detection system
  • X-ray system
  • sieves and filtration
  • optical system, including colour sorters and scanners
  • magnets
  • air or liquid separation systems and
  • the use of operatives, for example, as spotters, on bottle lines or illuminated inspection belts.