Whoa.... a recent study examined food microbiomes (community of microbes) of some foods and found that the foods contained many species of microbes - hundreds of species! The foods examined were a variety of masala spice mixes, cilantro, smoked salmon, cucumbers, and mung bean sprouts. Other studies have also found large numbers of bacterial species in all sorts of foods, including raw fruits and vegetables, cheeses, and fermented foods, such as kimchi. There are also bacterial differences between conventional and organic foods. No wonder it's good to eat a diverse diet - all those microbes that you're ingesting! A diverse gut microbial community in humans is considered healthy by researchers.
The researchers (all associated with the US FDA - Food and Drug Administration) looked at the bacterial "species richness" (number of different bacterial species) normally found on the 5 types of foods. They used modern genetic sequencing methods to analyze the food microbiomes and found a LOT of bacterial species ("high bacterial diversity"), as well as species unique to the different foods sampled - whether animal or plant based foods. They found not only beneficial species, but also species associated with food spoilage. Every food had some bacteria that could eventually lead to food spoilage (which makes sense - eventually all foods can spoil). Also, how the food was handled and packaged, as well as moisture levels, influenced the bacterial species found in the foods.
The masala spice mixes were especially rich in bacterial species (from from 968 to 1097) and in unique species (19), but the mixes also contained as many as 17 ingredients. Cucumbers had between 227 and 423 bacterial species, and 216 to 573 species for cilantro. Smoked salmon samples had fewer species - ranging from 89 to 181 species. An example of the diversity is that the cucumber microbiome is comprised of species within Proteobacteria (45 to 85%), Firmicutes (2 to 40%), Actinobacteria (8 to 31%), and Bacteroidetes (0 to 2%).
I don't know if one can ever replenish all the bacteria lost from years of antibiotics (e.g. for sinus infections - both chronic and acute sinusitis), but this is a good reason to eat a variety of foods - for all the species of bacteria. These bacterial species are not found in general probiotic pills - one must eat the foods to ingest the variety and richness of microbes. The researchers wrote: "Once established, the most likely source of new microbes joining our GI microbiome is the food we eat: each food stuff and commodity we consume likely contains a microbiome that passes through our bodies while nutritional ingredients and components are digested."
It is unknown how many of these microbes stick around in our body, but lots of research finds that a diet rich in fruits, vegetables, whole grains, seeds, nuts, legumes, some fish and meat (including poultry), some dairy - are beneficial to our gut microbiome, along with numerous health benefits. The fiber in these foods is also beneficial in that it feeds beneficial microbes. [see category NUTRITION for research, also Feeding Your Gut Microbes page.]
Excerpts from research by Karen G. jarvis et al in Frontiers In Microbiology:
Microbiomes Associated With Foods From Plant and Animal Sources
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