How long can spices be used once opened?

Depending on the ingredients, ketchup, salad dressing or mustard can last several months to a year .

Dr. Kimberly Baker, director of the Clemson Extension Food Systems and Safety Program (USA), explains that shelf life reflects the quality of the product, rather than its safety . This means you can still eat expired condiments, but the color, taste and texture are not at their best.

"Therefore, in addition to using on time , spices after opening need to be stored in the refrigerator. The temperature level should fluctuate at 4-5 degrees Celsius or lower to ensure product freshness," experts say.

Depending on the temperature and time of use, sauce products can be used for several months to several years. (Photo: Lisa Cherkasky/The Washington Post).

1. Tomato sauce: According to the US Department of Agriculture (USDA), tomato sauce can be used for 6 months after opening. Baker further explained that the long usage time is due to the product's high acidity, making it difficult for pathogens to grow.
2. Mustard: Also according to USDA recommendations, a jar of mustard after opening can be used for one year if placed in the refrigerator because of its low sugar concentration. Dr. Bryan Quoc Le, food consultant and author of the book Answers to 150 Food Science Questions , said that mustard seeds contain a lot of allyl isothiocyanate, a compound that creates the pungent flavor of mustard seeds. spice. Besides, this compound also has natural anti-bacterial properties, helping the product not spoil for a long time.
3. Mayonnaise: This is a family favorite and is used for sandwiches and salads. Baker said each jar of mayonnaise can be used for two months after opening, as long as it is stored properly.
4. Salad dressing: This product can be used for one to three months if kept in the refrigerator, but it still depends on the acidity of the ingredients.

In general, low-acid sauces (like buttercream) have a short shelf life, while highly acidic products (like vinaigrettes) can last for several months.

1. Hot sauce: Compared to other products, hot sauce can be used for one year after opening. The reason is because the vinegar content in spices can ferment, creating a natural preservative against harmful bacteria.

Hot sauce can be used for up to a year because of the high vinegar content in the product, which helps fight the growth of harmful bacteria. (Photo: iStock)

How to recognize spoiled seasoning

Although sauces and dipping sauces can last longer than other foods, when you detect a sour, fishy smell or mold or slime on the surface, you need to remove them.

Besides, contaminated spices also reduce their shelf life. To avoid this, food experts advise users to make sure the box lid is always tightly closed and cleaned after each use.