Please note that this post contains affiliate links and any sales made through such links will reward MageeNews.com a small commission – at no extra cost to you.
The most recent outbreak from Escherichia coli O157:H7 in romaine lettuce spurred me to pull up an old draft, trim it and post it in an attempt to promote public health. Enjoy.
In the Spring of 2017 while sprinkling balsamic vinegar over chopped romaine lettuce, I wondered if anyone had published on the bactericidal effect of vinegar on lettuce. That acetic acid is the most lethal of the organic acids is well known.
In addition to the most recent outbreak, (Marler 2018b) there have been several outbreaks involving lettuce (Marler 2018a). Thus a quick search of: Salmonella Vinegar Salad yielded Faith et alia 2012. Because they didn’t include Escherichia coli O157:H7 and the recent popularity of that pathogen in lettuce, there is room for additional work.
Therefore, I emailed some fellow food microbiologists with my findings averring there is still room for advancement of the science. It would be a good project for Extension and they might become as famous as Jillian Clarke or Robyn C. Miranda for their work on the “five second rule.” (Co-authors were Hans Blaschek and Don Schaffner.)
As the responses were lukewarm, I pursued this literature search. My fellow food microbiologists recommended that I develop the article into a paper for “Food Protection Trends.” Alas, requests for comments on FSIS’ proposed poultry and swine modernization have taken my free time until this outbreak.
Thus, this short article on making lettuce safer in the home. There are many opportunities and challenges to make lettuce safer at preharvest and before it enters homes but that is another project the Berry Et alia 2015 stimulated for me.
This is not a complete review but papers that would be useful to consumers. They are summarized in chronological order.
First:
Before treating your lettuce or other fresh greens, remove broken or bruised leaves. The breaks enable pathogens to enter the cells and thus, become protected from the lethal effect of the vinegar or whatever antimicrobial you use. Additionally, the liquid from broken or bruised leaves aids the multiplication of both good and bad bacteria associated with the produce (Takeuchi & Frank 2000, Brandl 2008).
Washing the leaves may reduce any unattached bacteria but has a poor effect on removing attached bacteria. There are many ways to sanitize or disinfect salad greens. Irradiation, cold plasma, electrolyzed water, and chlorine come to mind. But these are not readily available in most home kitchens. Thus, the purpose of this article: To review current science and offer practical recommendations to improve the safety of salads.
Second: Spoiler alert, vinegar kills pathogenic bacteria. Fans of the Law of Mass Action, will be happy that vinegar’s lethal effect is dependent on time, temperature, and the concentration of acetic acid (usually 6%). Balsamic vinegar, with its additional phenols is the cat’s pajamas of lethality.
Third: There’s plenty of science on the effect of vinegar.
My conclusions
Vinegar is a useful household sanitizing agent for leafy greens and other produce. But: What about blue cheese or Russian dressing? I don’t know. Haven’t seen any research. Personally, I would douse the lettuce with plain white vinegar then finish chopping the other salad ingredients. Finally give the greens a quick water rinse, shake (or spin), then toss the remaining ingredients with your favorite creamy dressing.
Greater time, temperature, or concentration increases the bactericidal effect. There are differences in the effect on leaves. Leaf surfaces differ in hydrophobic and hydrophilic substances. These affect both bacterial attachment and the ability of the treatment to contact the attached bacteria – or – virus.
Additional information Click Here
