UMass scientists partner with Real Pickles

The Recorder, September 27, 2018.

University of Massachusetts food scientists have mapped and characterized microbe populations at Greenfield’s Real Pickles factory as part of a study that might provide useful information to food processors worldwide.

The study at the vegetable fermentation facility showed that the microbiome was distinct between production and fermentation areas and that the raw vegetables themselves – cabbages destined for sauerkraut – were the main source of fermentation-related microbes in production areas rather than handling or other environmental sources.

This information could help food producers as naturally fermented food becomes more popular worldwide, researchers said. Writing in Applied and Environmental Microbiology,  researchers said this study helps to resolve the question of how microbes are transferred within a food fermentation production facility.

The UMass team collaborated with scientists from two units of the U.S. Food and Drug Administration’s Center for Food Safety and Applied Nutrition and another in Winchester.

Real Pickles is a worker-owned cooperative and makes pickles, sauerkraut, and other fermented vegetables the old-fashioned way, by natural fermentation and without starter microbial cultures or other media. Nutritional microbiologist David Sela notes that very little is known about the microbiomes of these facilities. Fermented foods are increasingly popular internationally, he adds, because of their enhanced nutritional properties, cultural history and tastiness, so the new information from this study should be of interest to food scientists, microbiologists and manufacturers around the world.

Sela said there is an “exciting explosion of interest in fermented foods and beverages we are experiencing locally in western Massachusetts and beyond.”

Company founder Dan Rosenberg said, “It’s fascinating to learn about the influence of fresh vegetables in establishing our facility’s microbiome and suggests that our use of organic vegetables is important to contributing a diverse microbial community to support fermentation. It raises interesting questions about how we can further improve our production practices to be producing fermented and probiotic foods of the highest quality. We’re excited to participate in research that improves understanding of fermented food production and nutrition.”

Sela said, “For the first time, we built a map of the facility and how it was transformed over time during fermentation, which has given us a more complete picture of the population in a real vegetable fermentation facility. Both cheese and beer have been done to a certain extent, but we feel that fermented vegetable facilities could be better characterized. And because we are using these new genomic tools, we have a better understanding of what is there and how they got there. Using the traditional approach, we couldn’t possibly culture everything, so we’d have a far more limited picture.”

The researchers report that Leuconostoc and Lactobacillaceae bacteria dominated all surfaces where spontaneous fermentation occurs. Also, they found that “wall, floor, ceiling and barrel surfaces host unique microbial signatures.”

Sela says next steps might be to see if similar findings may emerge in other vegetable processing plants around the world, whether seasonal changes might be observed and whether microbial populations change with different cleaning protocols.

“It’s not as important when making traditional sauerkraut,” he notes, “but some other food processing facilities might face more risk of spoilage and it would be interesting to see what microbes are present at various stages. Batches of food do get spoiled and we never see that as consumers, but it costs a lot when a whole batch is lost. We might be able to find a way to predict when that might happen by understanding the microbiological communities that surround the processes.”