Shelf life is not a fixed property of the product but the result of the conditions. The same strawberries keep for 5–7 days at 0 °C, 2 days at 10 °C and less than a day at 20 °C. A rough rule: the reactions that cause spoilage speed up 2–3 times for every 10 K. Example times: apples 3–6 months at 0 °C, carrots 4–6 months at 0 °C, lettuce 2–3 weeks at 0 °C, bananas 1–4 weeks at 13–14 °C, fresh red meat 1–3 weeks at 0 °C, fresh fish on ice from a few days to two weeks.
After temperature the second factor is humidity: low humidity means water loss and wilting, humidity higher than necessary means mould. The third is the condition of the product on entering the store; product that is bruised, cooled late or overripe at harvest keeps for only a short time even in the best room, because a cold store does not improve quality, it only slows the loss. Ethylene, air movement, packaging and the composition of the atmosphere also change the time: controlled atmosphere extends the life of apples to 8–10 months, vacuum packaging that of fresh beef to several weeks.
In frozen product deterioration does not stop, it slows. At −18 °C lean beef keeps its quality for about 12 months, chicken 9–12 months, oily fish 3–4 months and most vegetables 12–18 months; the same oily fish approaches 6–8 months at −25 °C and a year at −30 °C. What limits it is not microbes but rancidity of the fat and drying of the surface. Temperature fluctuation shortens these times noticeably; in a frozen store a constant temperature is worth more than a temperature a few degrees lower but unsteady.
There are two different dates on the label: for foods that spoil quickly microbiologically the "use by" date (the safety limit), for the others the "best before" date (the quality limit). Both depend on the storage condition stated on the label; if the condition is not kept, the date loses its meaning. The practical consequence for the store operator: first in, first out, continuous temperature recording and cooling the product as early as possible. The food storage conditions guide gives temperature, humidity and expected storage time together for dozens of products.