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One apple contains 100 million bacteria. As much as 90 percent of them are in the seeds of the apple, and almost all the rest – in the flesh. Microbes present in fruits from organic crops are healthier for humans.
Since microorganisms ingested with food can colonize the human intestine, scientists from the University of Technology in Graz checked the bacterial content of one of the most popular fruits. They compared the microorganisms present in industrially and organically grown fruit. They analyzed separately the peel, flesh, seeds and calyx, the place at the bottom of the apple.
Both types of apples had a similar number of microbes.
“We estimate that one apple weighing 240 g contains on average about 100 million bacteria” – emphasizes prof. Gabriele Berg, co-author of the study published in the journal “Frontiers in Microbiology”.
As much as 90 percent of them is found in the seeds, and almost all other microorganisms inhabit the flesh.
According to scientists, however, bacteria that live in fruits from organic farming are more beneficial to health
“Freshly harvested, organically grown apples contain a much more diverse, balanced and more clearly defined set of bacteria, compared to ordinary apples” – emphasizes Prof. Berg.
«It can be expected that this diversity and balance will limit too much growth of any species. Meanwhile, previous studies have shown a negative relationship between the number of human pathogens and the diversity of the microbiome in fresh vegetables and fruits »- explains the expert.
The lack of potentially dangerous microorganisms also works in favor of organic apples.
«Bacteria from the group of known pathogens Escherichia-Shigella were found in most conventionally grown apples, but in no organic apples. For the beneficial, probiotic Lactobacillus bacteria, we noticed an inverse relationship »- reported the researcher.
The microbiome of popular fruits can even affect their taste
«Methylobacterium, which is known to enhance the biosynthesis of the ingredients responsible for the strawberry flavor, was much more common in organic apples. There was especially a lot of it on the skin and flesh, which generally had a richer microbiome than seeds, petioles and calyx ”- says Prof. Berg.
Meanwhile, apples are not the only bacteria that live
«Our results are in clear agreement with recent studies on the apple-dwelling mushrooms. They showed the variety of mushrooms depending on the place in the fruit and the way of cultivation »emphasizes the main author of the study, Birgit Wassermann.
“The microbiome and the antioxidant content of fresh fruit and vegetables may one day become the primary consumer information provided along with macronutrients, vitamins and minerals. The key step will be to find out to what extent the food microbiome influences the microbial diversity of the gut and improves health »- says the researcher.