Can bacteria grow in vinegar?

This brief article will explore the query “Can bacteria grow in vinegar?” Also, we’ll explore what bacteria can be found in vinegar, what are the antimicrobial properties of vinegar, how vinegar is made, and how vinegar should be stored, 

Can bacteria grow in vinegar

No, bacteria cannot grow in vinegar, but it is possible to find some remnants of oxidizing bacteria that turn alcohol into vinegar within the solution. 

There are different species of acetic-acid forming bacteria, and their presence will depend on the concentration of acetic acid, as well as the raw material (type of alcohol) used to make vinegar.

Vinegar has an antimicrobial effect on foodborne pathogens such as E. coli and mold, as its acid content corrodes the walls of bacterial cells and disintegrates them, nullifying their processes and inhibiting their division. 

What bacteria can be found in vinegar

Depending on the acetic acid concentration and the provenance of the alcohol used to make vinegar, there can be one or more species of acetic acid bacteria present in vinegar.

These species can belong to one of the nineteen bacterial genera known to produce acetic acid, but the ones most commonly found belong to the genera:

  • Acetobacter
  • Gluconacetobacter
  • Gluconobacter
  • and Konagateibacter.

Acetic acid inhibits the growth of other bacterial types such as Salmonella, Escherichia, and Pseudomonas, to name a few. 

Determining exactly what bacteria are present in vinegar requires that the bacterial cells be isolated and purified from the acetic acid. 

This can be done by using solid or liquid growth media (a solution designed to provide the bacteria with their nutritional needs and promote their growth). 

Isolated bacterial types can then be sorted and determined by using different types of growth media, with some rich in sugars, others rich in nitrogen and minerals, etc. 

The media with the most bacterial growth will indicate the predominant bacteria’s nutritional needs, which will then be used to identify its genera and even species. 

What are the antimicrobial properties of vinegar

The antimicrobial properties of vinegar are rooted in its acidic nature. Acetic acid works in two ways: 

  • It inhibits the growth of bacteria by making the environment acidic, and ergo, less favorable. 
  • And the acid has a corrosive effect on bacterial cells and exposes their contents, without which, they can no longer maintain homeostasis, and cease all metabolic functions. 

Also, the antimicrobial properties of vinegar increase with the temperature, and with sodium chloride, both of which are commonly used to preserve foods. The combination of these two accelerates the inactivation of bacterial cells. 

How is vinegar made? 

Vinegar is a product obtained from fermenting alcohol with acetic acid bacteria. Strictly speaking, these bacteria oxidize ethanol (alcohol) and convert it into acetic acid, which is a type of carboxylic acid. 

What makes these bacteria unique is that they can withstand low pH levels (acid conditions), and can oxidize sugars, aldehydes, and alcohols, all in the presence of oxygen. 

Vinegar, be it homemade or at a commercial scale, is made following these general outlines: 

  • An alcohol source (such as cider, grain alcohol, etc) with 4-10% concentration is placed inside a sealing container.
  • Then, a quarter of the alcohol’s volume, but of live vinegar culture (acetic acid-forming bacteria) should be added.
  • Afterward, the container should be covered by a fabric or a mesh that allows the exchange of gas, as the acetic acid bacteria require oxygen to convert the alcohol into acetic acid.
  • The container with alcohol and vinegar culture will then be stored at a warm temperature, in the absence of light, to speed the fermentation process.
  • The fermentation will have begun, and the mixture will begin to acquire an acidic taste, aroma, and smell. After a determined period, the fermented solution can be strained and emptied into sterilized containers, where it can be sealed and left to mature, or packaged for retail. 

How should I store vinegar

Vinegar should be stored in a cool place without letting it be directly exposed to sunlight. Its acid content means it can be kept indefinitely and won’t spoil if properly stored. 

However, exposure to sunlight or ambient humidity will cause a decline in vinegar’s flavor, appearance, and overall quality, which may culminate in it being discarded. 

This can be averted by keeping it in a tight-sealing flask and storing it in a dry, well-ventilated pantry. 

Bacteria and other microorganisms won’t set in and grow, which ensures the long shelf life of vinegar.  

Conclusion

In this brief article, we’ve explored the query “Can bacteria grow in vinegar?” Also, we’ve explored what bacteria can be found in vinegar, what are the antimicrobial properties of vinegar, how vinegar is made, and how vinegar should be stored, 

References

https://www.streetsmartkitchen.com/does-vinegar-go-bad/

https://www.wikihow.com/Store-Vinegar

https://pubmed.ncbi.nlm.nih.gov/9713753/

https://www.news-medical.net/health/Does-Vinegar-Kill-Bacteria.aspx

https://bio.libretexts.org/Bookshelves/Microbiology/Book%3A_Microbiology_(Boundless)/17%3A_Industrial_Microbiology/17.4%3A_The_Microbiology_of_Food/17.4B%3A_Vinegar

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6117990/

https://www.insider.com/guides/health/does-vinegar-kill-germs-and-viruses

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Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.