How long does an unopened bagged salad last?
In this article, we will answer the question ‘how long does an unopened bag of salad last?’ and discuss the factors that affect the shelf life of an unopened bagged salad and how to know if the bagged salad has gone bad.
How long does an unopened bagged salad last?
An unopened bag of salad will last 3 to 7 days if properly stored in the fridge (or earlier based on the expiry date on the package) (2). It is possible that it can last even for 3 to 5 days after the expiration date when properly stored in the refrigerator unopened.
The shelf life of bagged salad depends on the storage conditions and type of product, as well as on many other factors, which will be discussed in the following sections of this article.
What are the factors that affect the shelf life of bagged salad?
The factors that affect the shelf life of bagged salad are related to handling, sanitation, initial microbial contamination of the vegetables, packaging and storage conditions. The main factors are (1,4):
- Salads are generally high in moisture and a common food rule says that food with high moisture content is more susceptible to microbial spoilage hence goes bad more quickly
- Temperatures above 8°C (46°F) favors microbial growth. Therefore, bagged salads should be stored above this temperature at all times, including during transportation
- The initial microbial contamination of the products may determine the shelf life, as a higher reduction of the initial bacterial load is required to achieve the minimum shelf life. Salads can be contaminated by water irrigation, soil and handling
- Packaging material: bagged salads are generally commercialized under modified atmosphere packaging (MAP), which are able to reduce the respiration rate of the salad and therefore improve the shelf life. Once opened, this modified atmosphere is broken and the respiration rate of both salad leaves and bacteria increase
- Hygienic practices and sanitation methods in the preparation of the bagged salad products are required to ensure safety and improve shelf life. If optimal food handling are not followed, the salad can be contaminated by pathogens
- Damage to the product: when the salad is physically damaged, microorganisms can act faster and efficiently, as they penetrate in the salad tissue
How to know that the bagged salad has gone bad?
To know that the bagged salad has gone bad, be aware of the possible indications of spoilage in the salad. The spoilage can be caused by the action of bacteria, fungi, yeasts and by the action of enzymes, which degrade the compounds in the salad. Some common signs of spoilage are (1,4,5):
- Generation of off-odors and off-flavors: microbial spoilage degrade the nutrients in the salad, resulting in the formation of off-odors and off-flavors, such as sour, putrid, alcoholic and fermented
- Generation of slime: slime is related to the action of bacteria and yeast. There is a change in the texture and bubbling can also occur
- Visual decay: rot and water soak on the bottom of the package, visual growth of bacteria and fungi
What are the risks of eating spoiled bagged salad?
The risks of eating spoiled bagged salad is of experiencing a foodborne disease. Ready-to-eat salads are susceptible to contamination of many pathogenic bacteria, yeast and mold.
Several food outbreaks are related to the consumption of bagged salads and related to the following bacteria: Escherichia coli, Salmonella, Shigella, Listeria monocytogenes and Campylobacter jejuni (4).
A study reported that about 67% of the commercialized ready-to-eat salads investigated within the expiry date were contaminated with Salmonella (1).
The common symptoms associated with foodborne illnesses are vomiting, diarrhea, stomach cramps and flu-like symptoms, such as fever and headache (6).
How to properly store bagged salad?
Bagged salads should be stored in the refrigerator and should not be kept unrefrigerated for more than 2 hours, due to the risks of fast microbial proliferation in food kept at temperatures above 5°C (40°F) (3).
A study showed that by simply reducing the storage temperatures from 12°C to 5°C (53°F to 40°F) it was possible to prevent microbial proliferation.
The microbial load of ready-to-eat lettuce increased from 2.9 log CFU/g on day 0 to 4.7 log CFU/g on day 5, when stored at 12°C, while at 5°C no significant growth was observed in the same period of analysis.
After the opening of the packages, bagged salads can be stored in the fridge for a maximum period of 2 days (1,2).
Other FAQs about Salad that you may be interested in.
In this article, we answered the question ‘how long does an unopened bag of salad last?’ and discussed the factors that affect the shelf life of an unopened bagged salad and how to know if the bagged salad has gone bad.
- Arienzo, Alyexandra, et al. Microbiological quality of ready-to-eat leafy green salads during shelf-life and home-refrigeration. Foods, 2020, 9, 1421.
- United States Department of Agriculture. Food Keeper Data.
- Luo, Yaguang, Qiang He, and James L. McEvoy. Effect of storage temperature and duration on the behavior of Escherichia coli O157: H7 on packaged fresh‐cut salad containing romaine and iceberg lettuce. J food sci, 2010, 75, M390-M397.
- Bencardino D, Vitali LA, Petrelli D. Microbiological evaluation of ready-to-eat iceberg lettuce during shelf-life and effectiveness of household washing methods. Ital J Food Saf, 2018, 10, 6913.
- Barth, Margaret, et al. Microbiological spoilage of fruits and vegetables. Compendium of the microbiological spoilage of foods and beverages. 2009, 135-183.
- Foodborne Illness and Disease. United States Department of Agriculture.