Monitoring a critical control point

The opening picture makes a point that sounds obvious but is missed constantly on busy shifts. A probe measures temperature only at its tip, in the exact spot where that tip is sitting. It tells you nothing about the rest of the food. Push it just under the surface and you read the outside, which heats up first and reads high while the middle can still be cold. That is the reading that gives false confidence and lets undercooked food through. The tip has to reach the one place that matters, which is the slowest part to heat, so the whole technique of probing comes down to getting the tip to the right spot and letting the reading settle before you believe it.

The rule is to read the thickest part, the core, and the reason is simple physics. Heat moves into food from the outside in, so the centre of the thickest part is the last place to come up to temperature. If you probe there and the core has reached a safe value, then everything between the core and the surface, which got hotter sooner, is safe too. Read the core and you have checked the worst case. Read the edge and you have checked the easy case while the worst case goes unmeasured. This is also why you avoid the bone when probing meat: bone conducts heat differently from flesh and can give a misleading reading, so you aim for the thickest part of the flesh itself. The core is the one place that tells the truth about the whole piece.

Good monitoring is four habits done every single time. First, read the core, the thickest part, away from surface and bone. Second, clean and disinfect the probe before use, after use, and between different foods, because a probe that has been in raw chicken will carry bacteria straight into whatever it touches next, and a dirty probe turns your safety check into a contamination route. Third, record the result at the time, as you take the reading, never later from memory, because a number remembered at the end of a shift is a number you have really only guessed. Fourth, use a probe you have checked, because a probe that reads wrong is worse than no probe at all: it gives you false confidence and a record that looks fine while the food is not. These four are the difference between going through the motions and genuinely knowing the food is safe.

A probe is only useful if it reads accurately, and probes drift over time, get knocked, and go wrong. The simplest way to check one is against iced water. A glass of properly iced water sits at about zero degrees, so you put the probe in, wait for it to settle, and a healthy probe reads close to zero. If it reads a couple of degrees off, it needs adjusting or replacing, and until then every reading it has given is in doubt. Many kitchens also check against boiling water, which sits at about one hundred degrees at sea level, to confirm the probe reads correctly at the hot end too. This quick check, done regularly, is what lets you trust the numbers you are writing down. Without it, you are relying on an instrument you have no reason to believe, and a monitoring record built on a faulty probe is worse than useless because it looks convincing.

This is the iced-water check from the previous slide, done with your own hands on three probes at once. Dip each one and read what it gives you. Probes A and C come back at 0.2°C and minus 0.3°C, close enough to zero to be trusted. Probe B comes back at 4.6°C in water that is sitting at about zero, which is well off, so that probe is faulty. The second half of the exercise is the part that matters on the floor. Probe B was the one used at the cook step this morning, and it showed 76.1°C on a chicken that was really nearer 71.5°C, under the limit the plan sets. The food was passed as safe on a number that was wrong, which is what the lesson means when it says a probe that reads wrong is worse than none. A probe that fails its check comes out of use, and every reading it has given is in doubt until someone works out how far back the fault goes. Follow the checking routine used where you work for how often probes are checked and what is done when one fails.

The scenario is an everyday one: you have probed raw chicken, and now you need to check a cooked beef joint on the same station. The right first move is to clean and disinfect the probe before it touches the beef. The probe tip has just been inside raw chicken, so it is carrying exactly the bacteria HACCP exists to control, and putting it into cooked, ready-to-eat beef would carry those bacteria straight onto food that will not be cooked again. Wiping it on a cloth is not enough, because a wipe does not disinfect and the cloth may add its own contamination. And the beef being already cooked is the very reason to be careful, not a reason to relax, because ready-to-eat food has no further cook step to save it. Between different foods, the probe gets cleaned and disinfected, every time. The instrument that checks safety must never become the thing that spreads a hazard.

The lesson in five lines. Take the reading at the thickest part, the core, not the edge. Clean and disinfect the probe before, after, and between different foods. Record the result at the time, never later from memory. Check the probe reads accurately, for example against iced water at about zero degrees. And remember what the whole exercise is for: monitoring confirms the critical control point is staying within its limit, which is the evidence that the food is being kept safe.

This is the first of six lessons in Level 3, and every lesson is free to watch for as long as you need. When you are ready, the quiz proves what you know and earns a certificate recognised by TrustBite, an independent food safety recognition body. One payment covers the quiz and certificate for all three levels, so whichever level you buy first, the other two are included at no extra cost, and each certificate is valid for three years with renewal at 5 euros. No registration is needed to keep learning, and you only pay when you decide you are ready to be tested. If you are training a team, group options are available for both hospitality and production sites.

You can now take a temperature reading you can trust, which is the foundation of everything else in Level 3. You know to read the core, to keep the probe clean between foods, to record at the time, and to check the probe is accurate. The next lesson takes the natural next step: what happens when that reading comes back out of limit. It covers deviations, how to recognise one, the corrective action you take, and when to escalate beyond your own authority. Every lesson stays free and you can rewatch any of them. When you are ready, the quiz earns a certificate recognised by TrustBite, and one payment covers all three levels.