How to know if blueberries are spoiled? (5 methods)

In this brief article, we are going to answer the question “how to know if blueberries are spoiled”, discuss the different methods of spoiled blueberries and tips to keep blueberries safe from spoilage.

How to know if blueberries are spoiled?

If you wish to determine whether your blueberries have spoiled, you can consider the following five signs as indicators:

Important: it is not recommended to eat spoiled blueberries as they contain harmful microorganisms and toxins that cause different foodborne diseases (1-5).

1. Mold growth: you should inspect your blueberries for any sign of molds growing on it. If you notice fuzzy or hairy patches, green or white growth, it indicates spoilage by fungi. 

You should not eat blueberries contaminated with molds as their mycotoxins can cause you severe food poisoning (6).

2. Discoloration: fresh blueberries are normally a deep blue or purple color. If you notice any significant browning, darkening, or a dull appearance, this a clear sign of spoilage. 

Pay attention to any alterations in the color of your blueberries and discard them promptly if significant color changes become apparent.

3. Soft or mushy texture: ripe blueberries should have a firm texture. If they feel excessively soft, mushy, or squishy, it may indicate that they have gone bad. 

When we hold spoiled blueberries, they exhibit a slightly jiggly or wobbly texture, indicating that they are no longer fit for consumption and should be disposed of.

4. Foul or off-putting odor: fresh blueberries have a pleasant, citrus and fruity sweet aroma. If you detect a strong, unpleasant odor, it suggests spoilage or fermentation. 

Smell your blueberries! If you detect an unpleasant odor, it means that your blueberries are no longer suitable for consumption. You should not eat them!

5. Taste test: while tasting spoiled fruits is not recommended, it can also serve as an indication of spoilage. If your blueberries have an off taste, such as sourness or bitterness, they may be spoiled.

If you observe any of these signs you stop eating your blueberries and throw them out immediately. 

Remember that your safety comes first!

Can you get sick from eating spoiled blueberries?

Yes, consuming spoiled blueberries can potentially put your health in danger due to the possible presence of harmful microorganisms, viruses, or parasites, which can lead to different health hazards (1-5).

Here are some examples of the main hazards and symptoms that you may experience after consuming spoiled blueberries:

• Gastrointestinal Issues: after eating spoiled blueberries you may experience nausea, vomiting, diarrhea which could be cause by bacteria like Salmonella, pathogenic strains of Escherichia coli or by other pathogens such as Campylobacter or Shigella (4).

• Food Poisoning: a common symptom of food poisoning by consuming spoiled blueberries is to experience abdominal cramps and fever. 

This symptom could be associated with various bacterial infections, including Clostridium perfringens, Staphylococcus aureus, Listeria monocytogenes and Salmonella (1,4).

• Bacterial Infections: eating spoiled blueberries can also cause you gastroenteritis and dysentery (7). 

Different pathogens like Vibrio parahaemolyticus, Yersinia enterocolitica and Shigella can cause inflammation of the gastrointestinal tract, resulting in severe diarrhea with blood or mucus (5).

• Viral Infections: eating spoiled blueberries may also expose you to viral infection such as Norovirus and Hepatitis A with associated symptoms like nausea, vomiting, diarrhea, stomach cramps, fatigue, jaundice, abdominal pain, and dark urine (3).

• Parasitic Infections: eating spoiled blueberries may also increase the risk of getting different parasitic infections such cyclosporiasis and giardiasis (8). 

These infections can lead to watery diarrhea, loss of appetite, weight loss, fatigue, abdominal cramps, and bloating.

It is worth noting that the probability of finding a particular pathogen in your blueberries can vary based on different factors, including how your blueberries were stored, your hygiene practices, and the origin of your blueberries.

Remember that it is very important to practice proper handling of your blueberries and check the above-mentioned symptoms of spoilage to decrease the risk of foodborne illnesses.

What should you do if you suspect you have eaten spoiled blueberries?

If you have consumed spoiled blueberries and are experiencing symptoms or suspect foodborne illness, we recommend you to monitor your symptoms, stay hydrated and seek promptly medical advice.

You should be alert for any indications of gastrointestinal discomfort, including symptoms of food poisoning such as nausea, vomiting, diarrhea, abdominal pain, or fever (9). Keep an eye on the duration and severity of your symptoms.

You should also drink plenty of fluids, preferably water, to prevent dehydration, especially if you are experiencing diarrhea or vomiting (10).

If your symptoms are severe, persistent and you have several concerns about your health, we highly recommend you to directly go to your doctor. 

A medical professional will offer suitable guidance and prescribe an appropriate treatment to your specific condition.

How to properly handle blueberries to avoid spoilage?

To properly handle your blueberries and prevent spoilage, you should consider the following tips:

• You should always choose blueberries that are plump, firm, and have a vibrant color. Please, avoid containers with crushed or moldy berries.

• If you plan to consume the blueberries within a few days, store them in the refrigerator to maintain their freshness. 

Place them in a breathable container or leave them in the original packaging, ensuring proper airflow.

• Remember that blueberries can typically stay fresh for about 5 to 7 days when properly stored in the refrigerator. However, their shelf life may vary depending on their initial quality and ripeness at the time of purchase (11).

• You should avoid moisture as it can accelerate spoilage. Only rinse the blueberries just before eating or using them. 

Excess moisture can cause mold growth and degrade the quality of the berries. Mycotoxins produced by molds could be very dangerous for your health (12)!

• If you want to store your blueberries for an extended period, consider freezing them. Rinse and pat them dry, then spread them out on a baking sheet in a single layer and freeze until solid. 

Transfer the frozen blueberries to a freezer-safe bag or container and store them in the freezer for up to six months.

• You should also handle your blueberries gently to prevent bruising or damaging the delicate fruit. Avoid storing heavy objects on top of them.

• Finally, you should always check your blueberries regularly and discard any moldy or spoiled berries to prevent the spread of spoilage to the rest of the batch or contaminating other foods.

It is recommended that you always rely on your senses and judgment to determine the freshness of the blueberries before consuming them.

Remember that your safety comes first!

Conclusion:

In this brief article, we answered the question “how to know if blueberries are spoiled”, and discussed the different methods of spoiled blueberries and tips to keep blueberries safe from spoilage.

References:

1. Cho K-B. Detection of Microbial Contamination in Commercial Berries. Biomed Sci Lett [Internet]. 2017 Dec 31 [cited 2023 May 18];23(4):333–8. Available from: https://www.bslonline.org/journal/view.html?uid=944&page=&pn=mostread&sort=publish_Date  

2. Trudel-Ferland M, Jubinville E, Jean J. Persistence of Hepatitis A Virus RNA in Water, on Non-porous Surfaces, and on Blueberries. Front Microbiol [Internet]. 2021 Feb 4 [cited 2023 May 18];12. Available from: https://pubmed.ncbi.nlm.nih.gov/33613487/ 

3. Leblanc D, Gagné MJ, Poitras É, Brassard J. Persistence of murine norovirus, bovine rotavirus, and hepatitis A virus on stainless steel surfaces, in spring water, and on blueberries. Food Microbiol [Internet]. 2019 Dec 1 [cited 2023 May 18];84:103257. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0740002018311961 

4. Nguyen TP, Friedrich LM, Danyluk MD. Fate of Escherichia coli O157:H7 and Salmonella on Whole Strawberries and Blueberries of Two Maturities under Different Storage Conditions. J Food Prot [Internet]. 2014 Jul 1 [cited 2023 May 18];77(7):1093–101. Available from: https://www.sciencedirect.com/science/article/pii/S0362028X23063639?via%3Dihub 

5. Pérez-Lavalle L, Carrasco E, Valero A. Strategies for Microbial Decontamination of Fresh Blueberries and Derived Products. Foods 2020, Vol 9, Page 1558 [Internet]. 2020 Oct 28 [cited 2023 May 18];9(11):1558. Available from: https://www.mdpi.com/2304-8158/9/11/1558 

6. Pleadin J, Frece J, Markov K. Mycotoxins in food and feed. In: Advances in Food and Nutrition Research [Internet]. Academic Press Inc.; 2019 [cited 2020 Apr 27]. p. 297–345. Available from: https://pubmed.ncbi.nlm.nih.gov/31351529/ 

7. Barrett J, Fhogartaigh CN. Bacterial gastroenteritis. Medicine (Baltimore) [Internet]. 2017 Nov 1 [cited 2023 May 18];45(11):683–9. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1357303917302177 

8. Almeria S, Cinar HN, Dubey JP. Cyclospora cayetanensis and Cyclosporiasis: An Update. Microorg 2019, Vol 7, Page 317 [Internet]. 2019 Sep 4 [cited 2023 May 17];7(9):317. Available from: https://www.mdpi.com/2076-2607/7/9/317 

9. Milaciu M V, Ciumărnean L, Orășan OH, Para I, Alexescu T, Negrean V. Semiology of food poisoning. Int J Bioflux Soc [Internet]. 2015 [cited 2023 May 10];8(2):108–13. Available from: http://hvm.bioflux.com.ro/docs/2015.108-113.pdf 

10. McRobert GR. THE TREATMENT OF BACTERIAL FOOD POISONING. Br Med J [Internet]. 1934 Aug 8 [cited 2023 May 10];2(3841):304. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2445530/ 

11. Huynh NK, Wilson MD, Eyles A, Stanley RA. Recent advances in postharvest technologies to extend the shelf life of blueberries (Vaccinium sp.), raspberries (Rubus idaeus L.) and blackberries (Rubus sp.). J Berry Res [Internet]. 2019 [cited 2023 May 18];9(4):709–24. Available from: https://eprints.utas.edu.au/32135/ 

12. Drusch S, Ragab W. Mycotoxins in Fruits, Fruit Juices, and Dried Fruits. J Food Prot [Internet]. 2003 Aug 1 [cited 2023 May 15];66(8):1514–27. Available from: https://pubmed.ncbi.nlm.nih.gov/12929850/