Cross-contamination essentials

What you are being asked to do

The Food Standards Agency expects raw food and ready-to-eat food to be kept apart, including the packaging, cloths, boards and machines that touch them. Safer Food, Better Business asks a catering kitchen to make that specific: where raw meat lives in the fridge, which board is used, when hands are washed, and how a surface is cleaned before it is used for salad, cake, or cooked meat. Your job on shift is to follow that method even when the pass is full.

Follow your own safe method if it is stricter. A kitchen with separate raw and ready-to-eat rooms does not abandon them on a busy Saturday because the ready-to-eat bench is nearer. A colour code on the wall outranks a habit you brought from another job. Businesses in Scotland should follow CookSafe as well as the separation rules in their own pack. The bacteria do not change at the border. The written method you are trained on does.

Two other modules finish the job this one starts. Hands are washed as the personal hygiene module describes, not rinsed. A surface that has had raw meat on it is washed and then disinfected, with the contact time, as the cleaning module describes. Wiping is not separating. Cooking temperatures are in the cooking module. They do not make a contaminated salad safe, because the salad is not cooked.

Why this one is not a "small slip"

E. coli O157 is the organism environmental health officers have in mind when they watch raw meat move through a kitchen. It can cause severe illness, including kidney failure, and it can do that from a very small number of bacteria. You will not see it, smell it, or cook it off a lettuce leaf. Campylobacter on raw chicken is a common cause of food poisoning in the UK and spreads easily from poultry juices onto hands, boards and salads. Salmonella travels the same routes, including from eggshells and raw meat. If your method keeps E. coli O157 off ready-to-eat food, it also helps with those others. If it only "usually" works, the low dose is what makes usually not good enough.

Ready-to-eat means the food will not get a thorough cook before the customer eats it. That includes salad, fruit, cooked meats, sandwiches, cakes, bread for service, cheese, garnishes, ice, and anything you have already cooked and are now slicing or plating. Raw means raw meat, poultry, fish, and unwashed vegetables that are still covered in soil, plus the packaging and drips that came in with them. Eggshells are treated as dirty even when the egg inside will be cooked. The line is the cook, not the menu heading.

Direct and indirect

Direct contamination is raw food touching ready-to-eat food: chicken fillets stored on a tray of ham, a raw burger plated on the same board as the bun, blood from a vac-pack dripping onto cheesecake. People notice the worst of these. Indirect contamination is the one that gets through on a busy shift, because the raw food has already gone and the bacteria have stayed on the thing you used next.

• Hands. After raw meat, its juice, or its packaging, hands carry bacteria onto taps, fridge handles, boards and then onto bread or salad. Gloves do not stop this. They move the bacteria until you change them and wash.
• Boards, knives and trays. A board used for raw chicken is a raw board until it has been washed and disinfected. Turning it over is not a clean.
• Cloths. A cloth that wiped a raw bench and is then wiped over the sandwich counter has done the travelling for the bacteria. This is the route staff forget because the cloth looks like cleaning.
• Probes and tongs. Probing raw then cooked, or turning raw chicken and then cooked chicken with the same tongs, puts live bacteria onto food that has finished its cook.
• Sinks and taps. Washing raw chicken, or rinsing a raw tray, sprays droplets. The tap you touch with raw hands is then the tap you touch before salad.
• Complex machines. Slicers, mincers and vacuum packers hide bacteria in joints you cannot see. A wipe of the blade is not a disinfection of the machine.

Storage: drips fall down

Raw meat, poultry and fish go below ready-to-eat food in a shared fridge. Drips fall. They do not climb. The bottom shelf, in a deep tray that can catch liquid, covered, is the raw place. Salad, cooked meats, desserts and anything opened for service sit above, also covered. If the bottom is full, you do not put mince on the top "just for this delivery". You move something, or you tell the manager that the fridge is too full to store safely.

Separate fridges are better where you have them: one for raw meat, one for ready-to-eat. Respect the labels even when one fridge is nearer the door. A raw fridge that someone has used for cream because the dessert fridge was full has stopped being a raw fridge. Put the cream back, and clean what it sat on before raw food goes back in.

Cover everything. An open tray of mince under an open tray of cooked chicken is two failures at once. Containers should be food-safe and intact. Cardboard meat boxes are often wet and are not a storage container in the fridge. Take the food out of the outer box, put it in a labelled container, and get the cardboard out of the kitchen. The outer packaging has sat on van floors and in cold stores. It does not belong on a salad bench either. When a delivery arrives, raw packs go straight to the raw area. They are not parked on the pass "while you find the delivery note".

Freezers follow the same logic. Raw meat above ice cream or ready-to-eat desserts is still a drip risk when bags leak or when food thaws during a breakdown. Thaw raw meat in the fridge, on the bottom, in a container. Thawing on a draining board lets the outside sit warm and lets juices run where they like. The chilling module covers the temperature side. The position of the tray is this module.

Prepare by place, or by time — never by hope

The safest kitchens have a raw area and a ready-to-eat area, with separate boards, knives, and, where they can, separate staff. You stay in the area you are given. If you must cross, you change the apron if it is soiled, and you wash your hands before you touch ready-to-eat food. You do not carry a raw tray through the sandwich section because it is a shorter walk.

Small kitchens often have one bench. Separation is then by time, and it is strict. You do the ready-to-eat work first, or you do the raw work, then you fully clean and disinfect, then you do the ready-to-eat work. You do not interleave them: a few chicken portions, then a quick salad, then the rest of the chicken. The Food Standards Agency is clear that using the same area for both, with cleaning between, carries more risk than physical separation. It is only acceptable when that clean is real. A spray and a wipe while the board is still greasy is not the clean the method requires.

Order the work so raw poultry is not out while salad is uncovered next to it. Put ready-to-eat food away, or cover it, before raw packs are opened. Soil-covered potatoes and raw meat are both "dirty" jobs. They still do not share a bowl of water with lettuce that is about to be served. Wash fruit and salad in a clean sink, in clean water, after the sink has been cleaned and disinfected if it was used for raw meat. Do not wash raw chicken or other raw meat. Splashes travel further than the sink. Pat or drain meat if you need to. The bacteria you were trying to rinse off are now on the tap, the splashback and your sleeves.

Boards, knives and the colour you were given

Use the boards and knives your kitchen has assigned. Many UK kitchens use a colour code: red for raw meat, blue for raw fish, yellow for cooked meat, green for salad and fruit, brown for vegetables that will be cooked, white for bakery and dairy. That list is a common habit, not a law you should invent if your wall says something else. Follow the chart in your kitchen. If there is no chart, stop using "whatever is dry" and ask the manager to set one. A code nobody can say out loud is not a code.

Do not flip a raw board. Do not use a cracked board that cannot be cleaned in the cut. Do not store raw and ready-to-eat boards in the same wet stack where water can sit between them. Knives follow the board. The red-handled knife does not "just slice the cheese" because the white knife is in the wash. If the only knife is the one you used on chicken, it is washed and disinfected before it touches food that will not be cooked again.

Chopping boards are only part of the surface. The table under a slipping board, the tray the chicken sat on, and the scales you weighed the mince on are the same problem. Weigh raw food into a container, not straight onto a scale that is then used for cooked portions, unless you can clean and disinfect the scale between those uses. Probe wipes live by the probe. Use one between raw and cooked checks, every time, including when you are in a hurry to record two temperatures on one sheet.

Cloths, aprons and the things that leave the raw area

A cloth is equipment. It is not a neutral object. Keep raw-area cloths in the raw area. Disposable cloth or paper is safer for ready-to-eat benches, because it ends in the bin instead of in a bucket. If you reuse cloths, they are washed in a hot cycle as your safe method says, and they are dried. A cloth left damp in a ball overnight is growing what it picked up yesterday. Do not tuck a raw cloth into your apron and walk to the pass.

Aprons and whites that are splashed with raw meat juices are raw protective clothing until they are changed. You do not slice ham in an apron you have just wiped your raw hands on. Hair nets and hats are not the main route, but your sleeves are. Roll them up or change if they are wet with raw juices before you handle ready-to-eat food. Outdoor coats and delivery bags stay out of the food rooms. The person who carried the raw chicken in does not lean the crate on the cake fridge.

Phones, pens and order pads move between dirty and clean hands all shift. If you have handled raw food, you wash your hands before you pick them up, or you accept that the phone is now a raw contact and you wash again after it. The better habit is to keep phones out of the prep area entirely. Money and card machines are not food equipment. Wash hands after taking payment before you make the next sandwich. The personal hygiene module has the handwash itself. This module is why the timing matters.

Sinks, salad, ice and garnishes

A separate sink for food, a separate sink for hands, and a separate sink or dishwasher for equipment is the layout officers expect to see described honestly. The wash-hand basin is never the pot wash and never the chicken rinse. If you only have one sink for food and equipment, it is cleaned and disinfected between raw use and ready-to-eat use, and raw meat is still not washed in it. Salad leaves and herbs are washed in clean water in a clean sink, then drained in a clean colander that does not live in the raw stack.

Ice is ready-to-eat. The scoop stays outside the ice, handle up, in a clean container, not buried in the ice where every hand grabs the food-contact end. A scoop that fell on the floor is washed before it goes back. Glasses are not used as scoops. The ice machine is not a dump for spare bottles. If you empty a drip tray, wash your hands before you touch the scoop.

Garnishes are ready-to-eat: lemon wedges, parsley, cucumber, the salad on the side of a steak. They are prepped on the ready-to-eat board, stored covered, and put on the plate with clean hands or clean tongs. They are not sliced on the edge of the raw board "because it is only a garnish". A raw burger bun that has sat against raw mince is thrown away, not wiped and served. Marinade that has had raw meat in it is not a finishing sauce unless it is boiled thoroughly as your method describes. The spoon you used to baste raw chicken does not brush the cooked chicken unless it has been washed, or unless you have poured a fresh portion of marinade that never touched the raw meat.

Slicers, mincers and vacuum packers

The Food Standards Agency's E. coli guidance treats complex equipment as a special case. Slicers, mincers and vacuum-packing machines should not be used for both raw and ready-to-eat food during the same day if you can avoid it. Bacteria sit behind the blade, in the carriage, and in the seals. A visible wipe does not reach them.

The practical rule in most small kitchens is: the slicer is for ready-to-eat food only. Cooked meats, cheese, and products that will not be cooked again. Raw meat is cut by hand on the raw board, or on a separate machine if you really have one. If a manager has a written method for changing a machine from raw use to ready-to-eat use, that method includes taking it apart and cleaning and disinfecting every food-contact surface, and it is not something you invent mid-service. You do not vac-pack raw mince and then vac-pack cooked ham on the same machine half an hour later because the bags are already out.

A mincer used for raw beef is a raw machine. Anything that comes out of it is raw, including the bit you "just tested" onto a plate that then goes near the salad. Wash your hands after you dismantle it. The pieces soak and are cleaned as the cleaning method says, not rinsed in the sink and called done because the metal looks shiny.

Flour, eggs and other foods people treat as harmless

Raw flour can contain harmful bacteria, including types of E. coli. Dough, batter and flour dust are not ready-to-eat. Do not taste raw mixture. Do not let children, or anyone else, eat cookie dough from the bowl. Clean flour off the bench before you prep sandwiches or fruit, because dust settles on more than the rolling pin. A bake that is fully cooked is the step that makes the flour safe. Licking the spoon skips that step.

Eggshells are a dirty surface. Crack eggs onto a clean surface, not onto the board you then use for ham. Wash your hands after handling shells. Egg boxes do not sit on the ready-to-eat fridge shelf above open desserts. Unwashed vegetables and the soil on them are a raw-side job. Once lettuce is washed, it is ready-to-eat and it stays on that side of the kitchen. Putting washed salad back into the crate the dirty lettuce arrived in puts the soil straight back on it.

Allergens travel on the same boards, cloths and fryers. That is a different hazard — a protein, not a bacterium — and it is not removed by a cook that would kill Campylobacter. A surface cleaned well enough for E. coli control is the start of allergen cross-contact control, not the whole of it. Follow the allergen module when the question is "does this contain milk, gluten, nuts", and follow this module when the question is "has raw chicken been near this".

When you think it has already happened

Stop. Do not try to rinse the salad and carry on. If raw juice has dripped onto ready-to-eat food, that food is thrown away. If you are not sure whether it dripped, ask the manager and say what you saw. Hoping it missed is how a tray of ham gets served after it sat under a leaking chicken pack. Surfaces and equipment that were hit are washed and disinfected before they are used again. Hands are washed. The cloth that wiped the drip is not used on the next bench. Write down what was thrown away and why. An officer would rather see a bin and a diary line than a full fridge you cannot explain.

If you only realise later — the raw board was used for the buffet, the same tongs did raw and cooked, the slicer did raw bacon and then cooked ham — tell the manager as soon as you realise. Food that has already gone out may be a business decision about customers. Food that is still in the kitchen can still be stopped. Silence until the end of the shift is the failure. You are not in trouble for reporting a mistake you can still limit. You are in trouble for plating the next order on the same board.

Worked example

A café does cooked breakfast until 11:30 and then switches the same two-metre bench to sandwiches and salad boxes. There is one fridge, one sink besides the wash-hand basin, and one slicer. Three things go wrong in the changeover unless someone runs it in order.

At 11:20 raw bacon is still on a red board, and a tray of raw sausages is sitting on the top shelf of the fridge because the bottom was full of yesterday's coleslaw. A reusable cloth has wiped the bacon board and is in the person's hand as they open the dessert fridge for butter. The unsafe version finishes like this: the sausages stay on the top shelf, the board gets a spray, the same cloth wipes it, and salad is chopped on that board at 11:35. The slicer, which sliced raw bacon at 9:00, is used for cheese at noon without being taken apart.

The safe version is slower and is the one the business can explain.

• Breakfast service finishes. Raw food is cleared first. The sausages move to a covered tray on the bottom shelf. The coleslaw, which is ready-to-eat, stays above, and anything that was underneath the sausages is thrown away because nobody can prove the packs did not drip.
• The red board and the bacon knife are washed in hot soapy water and then disinfected for the contact time on the product chart, as the cleaning method requires. They are put away as raw equipment. They are not flipped for the salad.
• The cloth is bagged for a hot wash. It does not touch the sandwich bench. A disposable cloth is used for the final wipe of the ready-to-eat surface and then binned.
• Hands are washed at the wash-hand basin after the raw clear-down, before the green board comes out. The apron, which is splashed, is changed.
• The sink is cleaned and disinfected before salad is washed. Raw meat is not rinsed in it.
• The slicer is not used for cheese until it has been dismantled, cleaned and disinfected, because it touched raw bacon. If there is no time to do that properly before lunch, cheese is sliced by hand on a clean board. The machine is not given a blade wipe and called ready.

At 11:50 the first sandwich is built on a dry green board. The diary line, if they had to throw the top-shelf risk away, says that sausages were stored above ready-to-eat food, the exposed coleslaw was binned, and the shelf was cleaned. That line is better than a full display you cannot defend.

What a manager or environmental health officer checks

Officers stand at the fridge and the bench and ask you to show the route raw food takes. They already know the answers they want. They are checking whether you know them.

• Open the fridge. Where is the raw meat, and what is above it? Is it covered, in a tray that can catch drips?
• Which board and knife are for raw meat today, and which are for salad? Can you say the colour code without looking at a poster you have never used?
• What did this cloth last wipe? Where are raw cloths kept, and how are they washed?
• Has this slicer, mincer or vac-packer been used for raw and for ready-to-eat food? If yes, show the dismantling clean, or show that it does not happen.
• Show me the wash-hand basin and the sink you use for salad. Is the basin blocked with a pot? Was raw meat washed here?
• How do you probe a raw burger and then a cooked one? Where are the probe wipes?
• If raw juice hit ready-to-eat food this week, what was thrown away, and where is that written?

A manager should be able to walk the same route without warning: raw food at the bottom, a colour code the team can say, cloths that do not travel, and a slicer with one job. The E. coli cross-contamination guidance from the Food Standards Agency, and the cross-contamination pages of Safer Food, Better Business, are what you are being compared with. They match the visit only when the person on the bench can separate raw and ready-to-eat while the officer watches.

You might be asked why a covered pack of mince still cannot sit on the top shelf. The expected answer is that covers leak, packs sweat, and one failure should not land raw juice on cake. "It was covered" is the answer that fails when the shelf below is ham.

Check your understanding

Doing this as part of your job?

If your workplace uses Localyn, ask your manager for your personal training link — completing modules through it records the training in the store's food safety evidence automatically. Managers: issue links from the Training page in your dashboard.

Related pages

Raw and ready-to-eat separationFIFO stock rotationOpening and closing checklistRestaurants