Pasteurization does not kill all microorganisms in food, it only reduces their amount to a safe level when they are unlikely to cause food poisoning. Vacuum packaging does not kill microbes. It only reduces the amount of oxygen available to them. This inhibits the multiplication of those microbes that need oxygen in order to reproduce. Food canning involves heating up the product to about 120°C for a certain time. This process kills not only bacteria but also bacterial spores, and as a result canned products can be stored in room temperatures for long periods of time.