Can you eat rx bars after the expiration date?

In this brief guide, we will address the query “can you eat rx bars after the expiration date?” and discuss the risks of eating expired protein bars. The rx bars are made from egg whites, dried fruit, almonds, and dates. 

Can you eat rx bars after the expiration date?

Yes, you can eat rx bars after the expiration date, unless there are notable signs of spoilage, such as bad odor and mold growth. In general, when properly stored, protein bars can be consumed after the expiration date.

However, it is not totally safe to consume expired rx bars. Protein bars are not free from microbial contamination and fungal growth, which can be harmful to health (1).

Thus, it is recommended that you eat the rx bars before the best before the date indicated on each packet for the best results.

What is the shelf life of rx bars?

The shelf life of RXBAR protein bars is, according to the website of the manufacturer Chicago Bar Company, a Kellogg subsidiary, is 10 months after the production date (3). 

The shelf life of protein bars can vary greatly, depending on factors such as the ingredients, the packaging material and the storage conditions. According to studies, the shelf life of protein bars that contain high amounts of fat and protein vary from 9 months to more than a year (2).

However, in the case of previous contamination of the ingredients or the contamination during the manufacturing process, which is possible, the shelf life is reduced to 3 months or less, depending on the storage conditions, as bacteria can spread rapidly to these types of food.

How to know if rx bars have gone bad?

To know if rx bars have gone bad you should be able to identify possible signs of spoilage. Protein bars contain high amounts of lipids besides proteins, due to their high lipid ingredients, such as nuts and seeds.

These ingredients can oxidize with time, even if stored properly. Lipids oxidize as a consequence of intrinsic factors (enzymatic and chemical reactions) and external factors, such as heat, oxygen and exposure to light (1).

Oxidation of lipids can lead to the loss of the nutrients and the generation of compounds such as aldehydes and ketones, which characterize rancidity (off-odors) and of-flavors (4).

Expired protein rx bars are usually darker than fresh produced bars (3). During storage, amino acids react with sugar in the so-called Maillard reactions, generating dark pigments and changing the nutritional profile (4).

The texture can become softer due to the increase in the moisture, however, depending on the ingredients, it can also become harder.

Bitterness is a characteristic of the flavor of oxidized protein bars. However, if you notice fungal growth on the surface, do not eat the bar. Although protein bars are considered having a relatively low water activity, (aw<0.80), they are susceptible to the contamination by yeasts and fungi.  

What are the risks of eating rx bars after the expiration date?

The risk of eating rx bars after the expiration date is of having a foodborne disease in the short term and to have inflammatory diseases in the long term.

In a short term, eating by bacteria contaminated protein bars can cause a foodborne disease with symptoms of diarrhea, vomiting, fever, stomach cramps and others. In a study, the pathogenic bacteria Bacillus cereus and Staphylococcus aureus were found in samples of organic protein bars (1).

Protein bars can also contain fungal toxins. Toxins can be harmful to humans and have mutagenic, carcinogenic and immunosuppressive effects. 

Oxidation of lipids leads to the formation of toxic compounds (1), which affect health in the long term, increasing the risks of inflammatory diseases (5).

How to store rx bars?

RXBARS are shelf stable, tha means, they don’t need to be refrigerated. However, you can refrigerate unopened bars as well as freeze them. Although they would be safe to eat, it is not recommended freezing the protein bars as it would compromise the texture and quality of the bar (3).

Refrigerating protein bars can reduce the oxidation rate and also reduce the development of microorganisms, extending the shelf life (1). However, if the packaging is opened, it is recommended to place it in an airtight container to reduce the moisture increasing.

Unopened rx bars should be stored in a cool place free from moisture and protected from heat sources (such as electronic equipment), as well as from light (6).

Conclusion

In this brief guide, we have addressed the query “can you eat rx bars after the expiration date?”. We have also talked about what rx bars are, their history, their varieties, their safety, how different rx bars are from others, and how to make rx bars at home. 

Citation

  1. Trząskowska, Monika, et al. Safety Assessment of Organic High-Protein Bars during Storage at Ambient and Refrigerated TemperaturesAppl Sci, 2022, 12, 8454. 
  2. Sharp, Matthew Alan Robinson. Development of a Shelf-Stable Caloric Dense Protein Bar Using a High Fat System. North Carolina State University, 2021. 
  3.  RXBAR Protein Bar. FAQ
  4. Pratiwi, Ivana Aprilia, Varongsiri Kemsawasd, and Thunnalin Winuprasith. Storage Stability of High Fiber Snack Bar. GHMJ, 2019, 3, 3.
  5. Vieira, Samantha A., Guodong Zhang, and Eric A. Decker. Biological implications of lipid oxidation products. J Am Oil Chem Soc, 2017, 94, 339-351.
  6. Van Laanen, Peggy. Safe home food storage. Texas FARMER Collection. 2002.

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