Cooking by time alone is guesswork. Internal temperature is the only reliable way to know food is safe — and the targets are more nuanced than most people realise.
Undercooked poultry kills. Overcooked steak is a tragedy. The difference between safe, delicious food and a food safety incident is measured in degrees — and a meat thermometer is the simplest, most reliable tool in any kitchen.
Salmonella, Campylobacter, and other poultry-associated pathogens are destroyed at 74°C. The higher threshold for chicken vs beef reflects where bacteria live: in whole beef cuts, bacteria are primarily on the surface (killed quickly), while poultry can harbour bacteria throughout the flesh, requiring the entire piece to reach temperature.
This is also why medium-rare chicken is never acceptable, while medium-rare beef steak is safe — the bacterial risk profiles are fundamentally different.
The official UK food safety guidance recommends 63°C for whole beef cuts (medium). Rare and medium-rare fall below this threshold — they are not technically "safe" by official standards, but the risk is very low for whole muscle cuts purchased from reputable sources. Minced beef is different: grinding distributes any surface bacteria throughout the meat, so burgers must be cooked through.
Meat continues cooking after you remove it from heat as residual warmth moves from the exterior to the centre. This means you should pull meat from the oven or pan slightly below your target:
This is not optional — it's the difference between perfectly cooked and overcooked. A chicken breast removed at exactly 74°C will be dry after resting; remove at 71°C and it reaches 74°C naturally while resting.
Insert into the thickest part of the meat, away from bone (which conducts heat differently). For poultry, check the thigh at the joint — the last part to reach temperature. For roasts, check the geometric centre. For burgers, insert from the side to reach the middle.