Tomato juice is a refreshing beverage rich in healthy antioxidants, including lycopene. However, like any other juice made from fruits or vegetables, it eventually spoils after opening. Once opened, commercially prepared tomato juice usually lasts about one week when refrigerated. Unfortunately, several factors can negatively affect your juice's shelf life, so always check your juice before drinking it to ensure it's still good.

Once opened, tomato juice should last for five to seven days if kept in a refrigerator set to 40 degrees Fahrenheit or below. Don't leave your juice out of the refrigerator for more than two hours, because temperatures higher than 40 F can lead to spoilage. To maintain your opened tomato juice for more than a week, freeze it at 0 F. Place it into a sealed container with at least 1/2 inch of empty space at the top to allow for the juice to expand when frozen. Tomato juice can last up to one year in a 0-F freezer.

Before drinking your tomato juice, give it a whiff to determine whether it's still good. If the juice smells sour or the normally reddish juice appears discolored, throw it out. Visible signs of mold within the juice are another sign of spoilage. Tomato juice also ferments over time because harmful spoilage microorganisms feed on it and give it an alcohol- or vinegarlike aroma. Due to the gases that these microorganisms produce, the container for the juice will expand and eventually burst. Don't serve tomato juice in a swollen container, because it is likely fermented and no longer drinkable.

Most commercially prepared tomato juices are pasteurized; those that aren't are usually labeled as such. If you aren't sure, ask the retailer selling your tomato juice. During the pasteurization process, the juice is heated to temperatures as high as 185 F to kill any harmful pathogens, like Escherichia coli or Salmonella spp., that could be in it. This not only extends the shelf life of the juice when unopened and opened but also prevents foodborne illness. Unpasteurized juices may last just a few days after opening and aren't recommended for people with compromised immune systems or women who are pregnant, warns the U.S. Food and Drug Administration.

At the first signs of spoilage, discard your tomato juice. While unopened tomato juice can last several weeks or months, once opened, contact with the air eventually leads to spoilage. Mold and other potentially harmful spoilage microorganisms can cause you to become very ill if you ingest them in spoiled juice; plus, the juice will taste awful. When making fresh tomato juice at home, only used freshly washed tomatoes that are free from any bruises or mold. Although tomatoes and tomato juice are high in acid and commercially prepared juice usually contains added vitamin C to keep the juice fresh, spoilage microorganisms can grow in the juice even when refrigerated.