The shelf-life of food is an important topic of conversation particularly in a world where food storage and food delivery has become more widespread. Keeping food fresh and unspoiled for a certain amount of time keeps it edible, nutritious, aesthetically pleasing, and tasty, all essential to the presentation of food.

Understanding the Shelf-Life of Food: When is Food Considered Spoiled?

Generally, food is considered spoiled when a consumer no longer deems it acceptable. The worst case of spoilage is when it becomes a food safety issue, where the food product may cause illness or in extreme cases death.

Less serious cases of food spoilage will find the color, flavor, texture, or aroma of the food has deteriorated to the point that it is no longer acceptable. When food has deteriorated to the point that it no longer meets its declared nutritional value, that is another case of spoilage. The time it takes for a food product to reach one of those spoilage conditions is generally termed the product’s shelf-life.

All foods naturally contain small amounts of bacteria. However, improper handling, cooking, or storage of food can result in the multiplication of that bacteria to the point that they can cause illnesses. In addition, illness can also be caused by parasites, viruses, toxins, and chemicals when they contaminate food.

Storage and refrigeration

Some food is more prone to harboring pathogens like bacteria or toxins that can make you sick. This is where refrigeration comes in. Refrigeration has long been a valid means to help in the storage and preservation of food, thus lengthening its shelf-life. Refrigeration is used in all stages of the chain, from food processing, to distribution, retail, and final consumption in people’s homes.

The global food industry employs both chilling and freezing processes. Food is cooled from ambient to temperatures above 0 °C in the chilling process while freezing entails temperatures between −18 °C and −35 °C. These are done to slow the physical, microbiological, and chemical activities that cause food deterioration.

While most of us are used to eating leftovers, that is often done with food that we assume is still safe to consume and within its shelf-life. Basic knowledge of the types of food, proper storage, and how they are prepared allows us to safely consume leftovers. Still, a common practice if to toss leftovers within three days.

Types of food for storage

Lower risk food

• Fruits and vegetables – When fruit is thoroughly washed and cleaned, they can keep for 3-5 days. Leftover vegetables, when cooked and stored in an airtight container, will keep 3-7 days in a refrigerator.
• Bread – Homemade bread can last three days at room temperature while store-bought bread is safe to eat for up to a week unless it develops mold. Storing bread in a refrigerator can extend their shelf-life by 3-5 days.

Higher risk food

• Cooked rice – Rice should be stored and cooled within an hour of cooking it because it can carry spores of Bacilius cereus. This bacterium produces toxins that can cause illness.
• Meat and poultry – Ground meat and poultry cooked to a safe temperature can last in a refrigerator for up to two days as long as it is stored at below 5 °C. Other meat and poultry, such as steaks, fillets, chops, and roasts, last 3–4 days in the refrigerator.
• Shellfish, eggs, soup, and stews – Since eggs can transmit Salmonella, shelled hard-boiled eggs should be consumed within a week of being cooked and refrigerated. Shellfish and fish should be consumed within three days because they can harbor many pathogens or toxins. Soup and stews generally last 3-4 days in a refrigerator.

Though shelf-life of food can be increased through storage and refrigeration, it is still more prudent to consume that food as soon as possible. The bacteria and toxins that different kinds of food can produce as they slowly deteriorate can swiftly turn nutrition-giving food into things that can instead harm the human body.

Learn about Other Healthy Eating Tips here.