Components of a synthetic cucumber juice medium influencing the growth and metabolism of Lactiplantibacillus species

Authors: Anthony, Allison; Breidt, Frederick

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2026
Publication Date: 2/11/2026
Citation: Anthony, A.M., Breidt, F. 2026. Components of a synthetic cucumber juice medium influencing the growth and metabolism of Lactiplantibacillus species. Journal of Food Protection. https://doi.org/10.1016/j.jfp.2026.100718.
DOI: https://doi.org/10.1016/j.jfp.2026.100718

Interpretive Summary: The basic microbial ecology and biochemistry of vegetable fermentations have been well studied, however, the biochemical factors in fermentation brines influencing fermentation quality and safety remain to be identified. This is partly because it is difficult to experimentally alter fermentation brine components that influence growth of the fermentation bacteria. To overcome this problem an artificial brine medium (ACJp) was developed that had similar chemical consistency as commercial cucumber fermentation brines. Using this medium laboratory experiments that chemical factors in brines could regulate bacterial growth rates, maximum extent of cell growth, final acid production and final pH. Because fermentation safety relies on pH and acid production, the results may be used to help commercial producers of fermented foods to diagnose problem fermentations and understand how to improve fermentation quality and safety.

Technical Abstract: An artificial cucumber juice medium has recently been developed (artificial cucumber juice, ACJ30) that has similar buffering capacity, nutrients and chemical components as a cucumber juice medium (CJ). The objective of this work was to determine how ACJ30 medium components (sugar concentrations, D- vs. L- malic acid, manganese and Tween 80) influenced fermentation with Lactiplantibacillus pentosus LA445, typical of the bacteria that dominate cucumber fermentations. L-malic acid is naturally present in CJ (approximately 9 mM), and anaerobic fermentations of ACJ30 media having D-malic acid, which is not metabolized by LA445, or L-malic acid resulted in similar biochemistry after 72 h, as buffering of D- or L-malic acid and pH controlled cell growth. However, LA445 in ACJ30 lacking malic acid rapidly lowered pH and had limited growth (log10 7.9 vs. log10 9 CFU/mL) and acid production 33.9 +/- 3 mM at 72 h compared to 111 +/- 3mM with L-malic acid or 93.9 +/- 4 mM for D-malic acid. By selectively varying non-buffering formulations of ACJ30 including Tween 80 and manganese concentrations, the LA445 growth rates, final CFU/mL, and fermentation acid production could be varied by 50% or greater. Using these data, ACJ30 formulations were designed to match the growth kinetics and fermentation chemistry of LA445 in CJ medium. Data from model fermentation systems with semi-defined media may aid in understanding how buffering and non-buffering medium components influence microbial ecology, safety and quality of fermented vegetable foods.