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Pickle spoilage bacteria may help environment

Date:
September 17, 2010
Source:
USDA/Agricultural Research Service
Summary:
Spoilage bacteria that can cause red coloration of pickles' skin during fermentation may actually help clean up dyes in textile industry wastewater, according to a new study.
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Bacteria that can color pickles' skin red during fermentation may turn out to benefit the environment by cleaning up azo dyes that impart red, orange and yellow color to fabrics which can end up in textile industry wastewater if untreated, according to new research by ARS microbiologist Ilenys Pérez-Díaz.
Credit: Photo by Peggy Greb

Spoilage bacteria that can cause red coloration of pickles' skin during fermentation may actually help clean up dyes in textile industry wastewater, according to a U.S. Department of Agriculture (USDA) study.

Some species of Lactobacilli-food-related microorganisms-can cause red coloring when combined with tartrazine, a yellow food-coloring agent used in the manufacture of dill pickles. Now Agricultural Research Service (ARS) microbiologist Ilenys Pérez-Díaz and her colleagues have found that these spoilage Lactobacilli also may have environmental benefits. ARS is USDA's principal intramural scientific research agency.

The scientists from the ARS Food Science Research Unit in Raleigh, N.C., noted that several Lactobacilli modify azo dyes, which are used in the textile industry and may wind up in wastewater if untreated. These azo dyes impart vivid and warm colors such as red, orange and yellow to fabric. Though many azo dyes are nontoxic, some have been found to be mutagenic.

This is the first report that food-related microorganisms can transform azo dyes into non-mutagenic substances. The findings from this work have been reported in the Journal of Applied Microbiology.

According to Pérez-Díaz, considerable effort has been made to identify microorganisms capable of degrading azo dyes in wastewater. If food-grade Lactobacilli capable of degrading a range of azo dyes were identified, they might become organisms of choice for wastewater treatment applications.

This discovery was made during Pérez-Díaz's search for the culprit responsible for causing some commercial dill pickles to have red spoilage bacteria. Pérez-Díaz and her colleagues isolated Lactobacilli from spoiled jars of hamburger dill pickles and used those isolates to inoculate non-spoiled jars of hamburger dill pickles. Jars that contained brines with tartrazine developed the red hue on the pickle skins; those that had turmeric or no added coloring did not.

Seven treatments were tested to find a preventive measure for red-colored spoilage. Pérez-Díaz found that adding sodium benzoate prevented bacterial growth and the development of red-colored spoilage in hamburger pickles.


Story Source:

The above post is reprinted from materials provided by USDA/Agricultural Research Service. The original item was written by Sharon Durham. Note: Materials may be edited for content and length.


Journal Reference:

  1. Roger F. McFeeters, Ilenys Pérez-Díaz. Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium Chloride. Journal of Food Science, 2010; 75 (3): C291 DOI: 10.1111/j.1750-3841.2010.01558.x

Cite This Page:

USDA/Agricultural Research Service. "Pickle spoilage bacteria may help environment." ScienceDaily. ScienceDaily, 17 September 2010. <www.sciencedaily.com/releases/2010/09/100917161157.htm>.
USDA/Agricultural Research Service. (2010, September 17). Pickle spoilage bacteria may help environment. ScienceDaily. Retrieved July 3, 2015 from www.sciencedaily.com/releases/2010/09/100917161157.htm
USDA/Agricultural Research Service. "Pickle spoilage bacteria may help environment." ScienceDaily. www.sciencedaily.com/releases/2010/09/100917161157.htm (accessed July 3, 2015).

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