The question of what happens when you eat expired food is a common concern that often leads to unnecessary food waste. The term “expired food” is misleading because most date labels on packaging relate to quality, not safety. Whether consuming food past its printed date will cause illness depends on the type of food and how it was stored, which determines the presence and growth of harmful microorganisms. For some products, passing the date means only a decline in flavor or texture, but for others, it signifies a genuine risk of foodborne illness.
Understanding Food Dating Labels
The dates printed on food packaging are not federally regulated in the United States, except for infant formula, which must include a “Use By” date to ensure nutrient content. This lack of uniform federal standards causes widespread consumer confusion and contributes to food waste.
A “Best if Used By” or “Best By” date indicates when a product is expected to be at its peak quality, flavor, and freshness, and it is not an indicator of safety. “Sell By” dates are primarily a tool for retailers for inventory management. A “Use By” date is the last date recommended for the product’s peak quality, but for highly perishable items, it can also signify when a safety risk may begin to increase.
Safety vs. Quality: The True Risk of Expired Food
The danger in eating food past its prime comes from contamination by pathogenic bacteria, which are distinct from the spoilage bacteria that merely affect quality. Spoilage organisms cause noticeable changes, such as mold growth, unpleasant odors, or sour tastes, which naturally discourage consumption. Consuming food with spoilage bacteria may result in a mild upset stomach, but it rarely leads to serious illness.
Pathogenic bacteria, like Salmonella, E. coli, or Listeria, are the silent threats that cause foodborne illness. These dangerous microorganisms often do not change the food’s appearance, smell, or taste, making them undetectable through sensory evaluation.
High-risk foods, such as raw meat, poultry, dairy products, and prepared salads, are susceptible to the growth of dangerous pathogens, especially if improperly handled or stored above 40°F. Low-risk foods, like shelf-stable pantry items or canned goods, may decline in quality long after their printed date, but they remain safe to eat indefinitely unless the container is damaged, bulging, or rusted.
Common Symptoms of Foodborne Illness
When food is contaminated with pathogens or the toxins they produce, the body’s reaction results in food poisoning. The most frequent symptoms include nausea, vomiting, abdominal cramps, and diarrhea, which the body uses to expel the harmful substances. A fever may also accompany the illness, indicating the body is mounting an immune response.
The time between eating contaminated food and the onset of symptoms, known as the incubation period, varies greatly depending on the specific pathogen. While some toxins can cause symptoms in as little as 30 minutes, most bacterial infections manifest between 12 and 72 hours after consumption. Symptoms typically last from one to seven days.
The symptoms experienced are often caused by toxins released by the bacteria, either while growing in the food or once the organisms are inside the body. For example, Staphylococcus aureus produces a heat-resistant toxin in food, leading to a rapid onset of illness. The most common serious complication of foodborne illness is dehydration, which occurs due to the body losing fluids through vomiting and diarrhea.
When to Seek Medical Attention
While most cases of foodborne illness are mild and resolve on their own, certain signs indicate the need for immediate medical intervention. Severe dehydration is a primary concern, identified by symptoms like lightheadedness, dizziness, extreme thirst, or dark-colored urine.
Medical attention should be sought immediately if symptoms are severe or persistent, such as vomiting lasting longer than two days or diarrhea continuing for more than three days. Other warning signs include bloody diarrhea or stool, a fever of 101°F (38.3°C) or higher, or intense abdominal pain. Neurological symptoms like blurred vision, muscle weakness, or difficulty breathing can indicate a rare but dangerous type of food poisoning, such as botulism.
For initial care of mild symptoms, focus on rest and replacing lost fluids with small, frequent sips of water or an electrolyte solution. Avoiding anti-diarrheal medications is often advised because they can slow the body’s natural process of eliminating toxins and organisms. Individuals who are pregnant, very young, over 60, or have a compromised immune system should contact a healthcare professional at the first sign of illness, as they are at a higher risk for serious complications.