At the start of an Australian summer with temperatures already soaring past the 40 degree mark, and the ongoing threat of “load shedding” causing more power blackouts, it is vital to understand the implications of the loss of electricity on the food in your refrigerator and freezer.

What is still safe to eat and what must be thrown out?

Australian health authorities suggest if power is off for less than 4 hours, unopened food should be fine, provided it has not gotten above 40 degrees. A full freezer will keep food at a safe temperature for up to two days if you keep the door shut.

However, foodborne bacteria can start growing in things like meat, poultry, seafood, milk and mayonnaise after it’s been kept above 40 degrees for more than two hours.

Authorities advise you do not rely on your sense of smell to determine if something is safe to eat. And tasting is even worse because that can lead to a foodborne illness like salmonella.

On a brighter note, if your frozen food still has ice crystals around it, it’s safe to eat.