FLC Region

Security Lab



3585 Greenville Rd # 2
Livermore, CA 94550
United States

Laboratory Representative


This laboratory develops screening assays, tests and modifies biosensor equipment, and optimizes food safety testing protocols for the military and civilian sector applications.


No Technologies


No Facilities


No Equipment


No Programs


No Funds


No Publications


No Awards


No News


Pickles have always been a popular food, but they are even trendier today as more and more craft brands show up in stores and farmers’ markets all over the country. But did you know that the USDA’s Agricultural Research Service (ARS) has helped commercial pickle makers, from small brands to the nation’s largest, meet the highest standards of food safety?

While pickling—storing in an acidic liquid, usually vinegar—has been recognized as a food-preserver since long before the discovery of bacteria, the kind of data that today’s precise food safety standards require was not established until recently.

In the late 1990s, incidents of bacterial contamination in acidic foods like unpasteurized orange juice and apple cider, which have the same pH as pickles, alerted the U.S. Food and Drug Administration (FDA) that pathogens such as Salmonella and Escherichia coli O157:H7 survived in juices at more acidic pH levels than previously believed—leading to new juice regulations. It also raised collateral questions about these pathogens in acidified foods, such as pickles, and prompted the FDA to issue draft guidance applicable to the pickle industry.

Even though there haven’t been any foodborne illnesses from commercial pickles in 50 years, no one knew exactly how to reach the 99.999-percent reduction in bacterial pathogens the FDA now considered appropriate. This also needed to be done without hurting the quality or taste of the pickles.

It was a job for researchers at the ARS Food Science Research Unit in Raleigh, North Carolina, the only national laboratory that works full time on the processing of commercially pickled vegetables. Every type of pickle and pickled vegetable would require its own study and set of numbers.

With significant support and funding from the pickle industry, the first ones the lab tackled were the pasteurized pickles—dill, bread and butter, sweet, sour, gherkin, kosher—the ones that pretty much dominate grocery store aisles. The researchers found that it took less than 1.2 minutes at 160°F (71°C) in brine at pH 4.1 to reach the 99.999-percent reduction level.

The scientists then moved on to the acidified, shelf-stable pickled vegetables like peppers and okra, which do not undergo pasteurization because they would fall apart in the heat. These products are instead made safe through the combined bacteria-killing effects of low pH and high organic acid concentration.

Today, all U.S.-produced pickled vegetables—a multibillion-dollar a year industry—are made following the standards set by the ARS Food Science Research Unit’s work.

This wasn’t the first time the lab revolutionized the pickle industry. For instance, John L. Etchells, the lab’s research leader from 1937 to 1975, improved the pickle fermentation process and reduced spoilage by a significant amount that pickles became much less expensive—making dill pickle slices a standard accompaniment on hamburgers in restaurants everywhere. Today, dill slices are 25 percent of the pickle market.

This post was originally featured on the USDA blog, to view, click here.

Pickles of many kinds fill grocery store shelves, all of them safe for consumers thanks to the work of an ARS food safety lab in Raleigh, North Carolina. (Photo credit: USDA)

An Agricultural Research Service (ARS) scientist in Wyndmoor, Pennsylvania, has shown that a relatively inexpensive steam-cleaner—designed to remove wallpaper and clean outdoor grills, kitchen counters, and other household surfaces—can rid cantaloupes, and possibly other produce, of Escherichia coli, Salmonella, and Listeria more effectively than existing washes and chlorine treatments.

The technology could reduce the number of foodborne outbreaks from contaminated produce, which each year cause an estimated 1.2 million illnesses, 7,100 hospitalizations, and 134 deaths. They also generate $1.4 billion in illness-related costs according to the U.S. Centers for Disease Control and Prevention.

Dike Ukuku and his colleagues at the ARS Food Safety and Intervention Technologies Unit in Wyndmoor submersed 24 cantaloupes in a bath inoculated with E. coli, Salmonella and Listeria strains, and then dried and refrigerated them at 41°F for 7 days. They then used a commercially available power steamer to steam-clean the cantaloupes by sweeping the spray nozzle across the fruit for 3 minutes. The nozzle was placed 3 inches from the cantaloupe, a distance that produced steam of 154°F at the point of contact, a temperature that was hot enough to kill surface pathogens but not damage the fruit.

The team used a 915 Wagner Power Steamer, but any steamer generating the same heat would likely produce similar results.

Some cantaloupes were cut up immediately after being steamed. Others were stored for 7 days at 41°F and then cut up.

The results showed that the steam treatment was effective at killing the pathogens. Pathogen levels were generally 1,000 times lower on the surfaces of steam-treated melons (99.9% reduction) and were undetectable on the cut-up pieces. Surface pathogen levels were about 100 times lower than those found on cantaloupes sanitized with chlorine.

The cut-up melon pieces showed no undue softening, discoloration or unwanted odors, either right after the treatment or up to 7 days later. The researchers refrigerated treated melons for 29 days to check for abnormal ripening, decay, and defects—and found none.

The technique may also be used to sanitize watermelons, honeydew melons, cucumbers and baby carrots, Ukuku said.

Ukuku realizes that consumers are unlikely to start “steam-cleaning” their produce, but his work shows that the technique could be used to sanitize produce without significantly adding to food processing costs. Processors and distributors could apply steam when cantaloupes are put into washers or as they pass along on conveyor belts during processing, he said.

The original article, which appeared in the March 2017 issue of USDA’s AgResearch Magazine, can be viewed here.

Foodborne illnesses from contaminated produce sicken 1.2 million people each year in the United States. A USDA study shows that steam-treating cantaloupes can reduce pathogens. (Photo credit: USDA)


No Licenses