One Board, One Sink, Two Jobs
A 24-seat kottu and rice-and-curry shop has two sinks: one in the washing-up area and one at the front counter. The counter sink is used by staff to wash hands, to rinse raw chicken before marinating, and to fill water jugs. There is one 60 cm cutting board. Raw chicken is cut on it at 10:00; at 11:30 the same board is wiped with a damp cloth kept in a bucket of water and used to slice tomatoes and boiled eggs for the lunch service. The cloth is rinsed only at the end of the shift. The cook says he wipes the board 'because it looks clean'. Three new helpers started a fortnight ago and have had no training; one of them also uses the counter sink to wash his hands after handling chicken, then dries them on his apron. Chicken is cooked to order in a very hot wok. The owner says business is slow and he cannot afford new equipment.
1. Identify the cross-contamination routes in this kitchen and rank them by risk, justifying the ranking.
Read the worked answer
Ranked by the probability of contaminating food that will not be cooked again:
- The single board used for raw chicken then for tomatoes and boiled eggs. Both later items are ready-to-eat. Raw chicken liquor, with Campylobacter and Salmonella, is left on the board; a wipe with a damp cloth redistributes it rather than removing it. There is no kill step before the tomatoes reach the customer, so this route has the shortest path from hazard to illness.
- The damp cloth in a bucket of water. A wet cloth at ambient temperature is an ideal growth reservoir: it picks up organisms from the board, spreads them across every surface it touches, and is only rinsed at the end of the shift. It is worse than no cloth, because it creates the appearance of cleaning.
- The counter sink that doubles as a hand-wash basin and a chicken-rinse station. Rinsing raw chicken splashes contaminated droplets onto the tap, the sink rim and the surrounding counter; the next person to 'wash hands' there coats their hands in the same contamination. This route is insidious because the staff genuinely believe they have washed their hands.
- Drying hands on an apron, and no training for three new helpers. These are multipliers - they convert a single lapse into a routine practice and make every other route more likely.
Note the wok is not the problem: it is hot and it kills. The failures all sit after the cooking step, which is precisely where cross-contamination does its damage.
2. Given that the owner cannot buy new equipment, what single change would reduce risk the most, and how would you implement it?
Read the worked answer
Separate raw work from ready-to-eat work in time, and make cleaning between them a real step. Time separation costs nothing and breaks the highest-risk route.
Implementation
- Set a fixed prep sequence: all ready-to-eat preparation (tomatoes, boiled eggs, garnishes, salad) is done first, from 08:00 to 09:30, before any raw chicken is handled. Raw chicken is cut and marinated from 09:30 onwards and never before the cold items are covered and stored.
- Between the two phases the board and bench receive a two-stage clean: detergent wash, rinse, then sanitise with a freshly made chlorine solution (about 100 ppm, made with a measuring scoop and tested) or by pouring boiling water over the board and leaving it to air-dry. A wipe with a damp cloth is not a clean.
- Ban rinsing raw chicken altogether. It spreads bacteria through splash with no benefit - the wok does the killing.
- Move the chicken rinsing off the hand-wash sink permanently. Hands are washed there and nowhere else; the washing-up sink is used for raw meat equipment. If the owner truly cannot buy a board, a large plastic tray or a sheet of food-grade plastic can be dedicated to raw chicken and washed after use - but a second board is one of the cheapest items in the kitchen and the argument about cost is weak against the cost of an outbreak.
- Replace the bucket cloth with single-use disposable cloths or a small stock of reusable cloths that are changed every four hours, washed hot and dried before reuse.
3. How would you verify that the new practices are actually being followed, rather than just written down?
Read the worked answer
Verification has to be observable and recorded, otherwise it collapses on the first busy day.
What to check, and how often
- A short daily opening check by the person in charge: board visibly clean and dry before ready-to-eat prep, sanitising solution made and tested that day, hand-wash basin stocked with soap, running water and single-use towels, cloths not sitting in a bucket. Signed and dated.
- Observation, not interrogation. Watch a helper through one full raw-to-ready transition. Ask them to show you how they clean the board. If they reach for the damp cloth under the counter, the training has not landed.
- Sanitiser strength testing with test strips or a kit, at least once per shift, with the reading recorded.
- Hand-wash spot checks: basin free of utensils, soap present, no apron-drying. Correct on the spot, every time, so the standard is visibly enforced.
- Trace a batch: pick a lunch service and ask who prepped the tomatoes and when, relative to the chicken prep. If nobody can answer, the sequence rule exists only on paper.
- Training records for the three new helpers, with a practical demonstration signed off, not just a briefing.
Corrective action when a check fails: retrain immediately, re-clean, and record the failure and the fix. Repeated failures in the same step indicate the design of the task is wrong - for example, the hand-wash sink is in the wrong place - and need a layout change, not another lecture.