“An apple a day keeps the doctor away.” The explanation behind this old saying can be found in the abundance of vitamins, minerals and other antioxidants in this fruit, but not solely: apples are also an important source of microorganisms (bacteria, viruses, fungi) with many health benefits, which colonize and temporarily enrich our gut microbiota. Few studies have discussed these “good” microbes since most of them focus on microorganisms responsible for foodborne illness. This oversight has been corrected thanks to an Australian team, whose findings are published in the Frontiers in Microbiology journal.
Organic food provides greater diversity
Researchers analyzed all microorganisms hidden in flesh, skin, stem and seeds of apples, as well as the impact of the cultivation method used. Their first observation was that most bacteria are concentrated in the stem, seeds and calyx, which we usually do not eat. But flesh and skin also contain higher concentrations of bacteria. Another finding from the study was that the microbiota of organic apples while not more abundant was much more diversified and more homogeneous than that of conventional apples. This could limit the presence of harmful microorganisms that may cause foodborne illness. And good news: diversity was highest in the organic fruit’s flesh.
Bacteria that are good for our health
The study out of Australia also showed that organic apples mainly contain lactobacilli, with well-known beneficial properties, as well as another bacterial type responsible for the taste of strawberries. As to the microbiota of ordinary apples, it is strongly dominated by Enterobacteriaceae, a family of bacteria including some species (such as Escherichia coli) that are responsible for foodborne illness. The authors believe that these differences in microbial composition are due primarily to agricultural practices and storage conditions. And they hope to see, one day, this nutritional profile indicated on marketing labels, together with the content of macronutrients, vitamins and minerals.
