Ketchup can be a deceptive condiment. Left out at room temperature for hours at parties, restaurants, and grocery stores, the shelf life of a bottle of ketchup may appear endless.
Ketchup purchased in a bottle can be left out overnight if unopened. However, the bottle should be refrigerated after the seal has been broken to ensure quality during long-term storage. Homemade ketchup should be refrigerated and never left out overnight.
Despite the common recommendation to refrigerate ketchup, there is some reason to believe that ketchup could be safely left out overnight. This article may help you determine the best way to store ketchup in your unique environment.
How Long Can Ketchup Be Left Unrefrigerated?
Store-bought ketchup can be left unrefrigerated for an indefinite amount of time, although the quality will deteriorate after one week. The pH level of manufactured ketchup sold in a bottle is low enough that it is not considered a TCS food.,
A TCS food, according to national ServSafe guidelines, needs time and temperature control for safety. This often means controlling refrigeration and minimizing time left out at room temperature.
Most TCS foods have a pH classified as slightly acidic or neutral (4.0 to 8.0 on the pH scale). Ketchup has a pH of 3.9, which is just below the level where pathogens are likely to rapidly grow.
The maximum amount of time that ketchup could potentially be left out unrefrigerated is 30 days. Notice any change in smell, color, and texture after opening. When in doubt, throw it out!
What Happens When Opened Ketchup Is Left Out?
When an opened bottle of ketchup is left out, the air makes contact with the sauce and starts the process of oxidation. This may change the color from ruby red to dark maroon.
The flavor of a freshly opened bottle of ketchup will differ from one that has been left out at room temperature for more than a week. The sweet and sour flavor will disappear and be replaced with something funkier.
However, ketchup is not the only touchy sauce sold in a bottle. For more information on which condiments can be left out at room temperature, we recommend reading this article.
What Happens If You Eat Ketchup That’s Gone Bad?
The FDA receives 50 to 100 reports of severe food poisoning from ketchup annually. Sometimes this is from consumption of ketchup after the expiration date. Other times, it’s from contaminated tomatoes in the sauce during manufacturing.
According to the CDC, mild symptoms include stomach cramps, nausea, vomiting, fever, and diarrhea. Severe food poisoning symptoms include bloody diarrhea, a fever over 102 degrees F, diarrhea that lasts for more than three days, and dehydration as a result of frequent vomiting.
If you believe you have eaten ketchup that has gone bad, you should seek professional medical advice immediately. There is a risk of bacterial foodborne illness from improperly stored ketchup.
How Can You Tell If Ketchup Has Gone Bad?
Always read the label on the ketchup bottle and note the expiration date. Ketchup is past its prime once there is a funky odor and it no longer smells like tomatoes.
If there is noticeable mold growing on the ketchup, it has gone bad. When mold starts to form on top of ketchup, it can range in color from white to yellow to blue. If a spoonful of ketchup from the bottle appears to have melted cheese on top, that is a sure sign of mold growth.
The viscosity of ketchup can hint at spoilage. Instead of a smooth, homogeneous puree, the vinegar will separate from the tomato base and appear runny. If the ketchup has not passed its expiration date but has an altered taste, appearance, texture, and odor, it should not be consumed.
How Should Ketchup Be Stored?
As a general rule, an opened bottle of ketchup should be stored with its original lid at 41 degrees F or lower in the refrigerator. Newly homemade ketchup is best stored in the fridge at 41 degrees or lower in a mason jar with a lid. There are exceptions that are explained later in the article.
If using Tupperware or glass to store homemade ketchup, make sure the amount of ketchup matches the size of the container. If the container is too big for the amount of ketchup it’s holding, the sauce could risk too much air exposure and increase the rate of spoilage.
When preparing and canning ketchup from scratch, consider using smaller jars. This will reduce the amount of time the ketchup is exposed to air before it is eaten, giving it less chance to spoil after opening.
Ketchup prefers a dark environment. Leaving it out in the light will cause it to spoil more quickly. Pantries and refrigerators offer a dark safe haven for this condiment.
Why Do Some People Leave Ketchup in the Pantry?
In 2017, there was a Twitter war between people who stored ketchup in the fridge and those who stored it in the pantry. Both sides argued that their storage method was the best. History may reveal why there was a split in consensus.
Ketchup, as we know it today, derives from the Indonesian fish condiment known as “kecap.” When British and Dutch merchants traveled to Asia in the 1700s, they used kecap to flavor their rations of hardtack and salt pork because it was shelf-stable and did not spoil on prolonged voyages.
Fermentation is the reason the original ketchup or “kecap” did not spoil. Charles Lockyer, a British merchant for the East India Company, bought large quantities of kecap abroad. He bottled the sauce and brought it back to England, selling it as a highly-priced luxury good.
Imitation recipes cropped up in cookbooks around England and the name was changed to “ketchup” or “catsup” in the English language.
One ingredient the English had on hand was vinegar, which is still a modern ingredient in the mass-produced version of ketchup sold on shelves today.
In the 1800s, cooks started adding tomatoes to their homemade ketchup sauces. By the mid-1850s, fish was no longer a key component of the ketchup recipe, and the flavor profile morphed into the modern sweet and sour combination we know today.
Both sugar and vinegar act as effective preservatives in ketchup which is why some people argue that ketchup can be safely stored in the pantry after opening.
After all, one 1817 British recipe for “tomata catsup” claims that it could “keep for seven years.” The 1817 iteration calls for tomatoes fermented with salt for three days and a wine glass of brandy added to each bottle.
The modern Heinz ketchup sold in supermarkets across Europe and North America does not contain preservatives such as benzoates and sulfates that would extend its shelf life at room temperature. The Heinz ketchup recipe contains the following ingredients:
- Sugar
- Vinegar
- Tomato paste
- Brine
- Spices
To make bottled Heinz ketchup, there is no fermentation involved to increase shelf life. The tomato mixture is simply heated and cooled before it is bottled and sealed. This is another reason Heinz ketchup should be refrigerated after opening.
However, many people will argue that the acidity of the tomatoes and the acidity of the vinegar are enough of a preservative to leave ketchup in the cupboard unrefrigerated. Vinegar is, in fact, a product of fermentation.
How Long Can Ketchup Last When Stored Correctly?
Bottled ketchup purchased from the supermarket can last one to six months in a 41-degree F fridge after the seal has been broken. Restaurants keep large tubs of ketchup in their walk-in cooler and refill their ketchup bottles daily before each service to ensure food safety and product quality.
Homemade ketchup stored in a container such as Tupperware in the fridge can last three to five days, depending on the ingredients and how old the ingredients were when they were added to the recipe. If the homemade ketchup is stored in a jar sealed with a pressure cooker, it can withstand more time in the fridge.
To make truly fermented ketchup from scratch without vinegar, a live-culture starter can be added to the cooked and cooled tomato mixture. This homemade ketchup can be canned and pressure sealed to last three weeks in the fridge or six months in the freezer.
An unopened bottle of store-bought ketchup will last one year in the pantry. Unopened homemade ketchup jars that have been sealed with a pressure canner will last six months to one year when stored between 50 and 70 degrees F.
However, be aware of the possibility of the bacterial foodborne illness Clostridium botulinum from improper canning.