That’s what some people call this common bit of folklore: if you drop food on the floor, pick it up within three seconds or so and it will be fine to eat. Wrong. Even a nanosecond is enough for food to have a brief and fruitful affair with myriad bacteria that gets traipsed over the kitchen floor by footwear that has trodden upon footpaths, public toilet floors, bus aisles and office carpet squares.

The worst thing to do, says Lydia Buchtmann, of Food Standards Australia New Zealand, is to pick up food from the floor and slip it into something that will not be cooked, such as a salad or a dessert: “The bugs picked up can grow to dangerous levels very quickly and give you food poisoning.”

Says who? The distress that many a rice or pasta salad has caused after being left out for hours at a languorous summer picnic . . . When these foods (and other cooked items) enter the temperature “danger zone” of five to 60 C, Bacillus cereus can form heat-resistant spores and a heat-resistant toxin. “Cooked food should not be stored in the refrigerator for more than two to three days,” says Buchtmann.