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| When is food left unrefrigerated safe to eat? | to Top |
First determine if the food is highly perishable or not. Perishable food held in the danger zone (50 to 120 F, 10 to 49C) for over 3 hours (2 hours at very warm temperatures) should be discarded because pathogens may have multiplied.
Examples of foods that will have only quality spoilage are those with sugar content so high that the microrganism growth is inhibited such as jams, jellies, frostings (including seven minute), syrups, and cakes. This does not include all sweet foods. Some desserts still have enough for pathogen growth such as soft meringues, cornstarch and tapioca puddings, custard pies, and custard-filled pastries.
Examples of foods that are less perishable due to their low moisture include bread, jerky, dried fruits and vegetables, dried pasta, and hard meringues.
Examples of foods that will have only quality spoilage due to their high acid content include salad dressings, mayonnaise, cream cheese frosting, vegetables and fruit pickles, fruit juices, and cooked fruits in juice or syrup (such as opened jars of canned fruits). Fruit pies are both low in pH and contain sugar. These foods will spoil in time, but the spoilage is by nonpathogens or by visible mold. Combination foods that contain both potentially hazardous and less perishable items should be handled as perisbhable. Examples include mayonnaise and macaroni salad, mayonnaise and tuna mixtures, and meat loaf sandwiches.
Some foods are nonperishable when purchased, but after cooking and/or rehydration become perishable such as rice, macaroni, and dried soup mixes.
Raw foods are usually not a good environment for pathogens to grow. Fresh fruits and vegetables are safe to consume unless grown in contaminated soil or with unsafe water. Raw meats, fish, and poultry are a special case. It is advisable to thaw raw meats, fish, and poultry at temperatures below 40F (4C), and to store them in an ice chest if the trip home from the market is long or the weather particularly hot because growth of pathogens is possible. This increases the risk of cross-contamination during its preparation for cooking. However, when these recommendations are not followed, the food is still safe to consume after cooking well because most pathosens, such as S. aureus, are poor competitors with other microorganisms on raw foods and also because thorough cooking kills the bacteria that cause foodborne illness. A notable exception is scombroid poisoning caused by spoilage of raw fish. VanGarde, Shirley J. and Margy Woodburn. 1994. Food Preservation and Safety. Principles and Practice. Iowa State Press, Ames Iowa., p. 38
Updated: Saturday, December 29, 2007.
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