You must have heard this common proverb, which goes like- 'an apple a day keeps the doctor away'. There is no denying the fact that apple is replete with essential nutrients and can turn out to be quite beneficial for your overall health. However, a recent study, published in the journal Frontiers in Microbiology, compared the bacteria in conventional store-bought apples with those in visually-matched fresh organic ones. It was found that a typical 240-gram apple contains about 100 million bacteria. Yes, you read that right! But whether these bacteria are good or bad, this may depend upon how the apples were grown.
"The bacteria, fungi and viruses in our food transiently colonise our gut. Cooking kills most of these, so raw fruit and vegetable are particularly important sources of gut microbes," said Professor Gabriele Berg from Graz University of Technology in Austria.
For the study, the researchers analysed the stem, flesh, seeds, peel and calyx of the apple separately. It was found that overall the organic and conventional apples were occupied by similar numbers of bacteria.
"Putting together the average for each apple component, we estimate a typical 240-gram apple contains roughly 100 million bacteria," Berg informed.
However, the question remains whether these bacteria are good for you or not?
Since organically-grown apples harbour more balanced and diverse bacteria, it may make them tastier and healthier than conventional apples.
"Freshly harvested, organically-managed apples harbour a significantly more diverse, more even and distinct bacterial community, compared to conventional ones," explained Berg.
"Escherichia-Shigella -- a group of bacteria that includes known pathogens -- was found in most of the conventional apple samples, but none from organic apples. For beneficial Lactobacilli -- of probiotic fame -- the reverse was true," said the researchers.
Methylobacterium, known to enhance the biosynthesis of strawberry flavour compounds, was significantly more abundant in organic apples, "especially on peel and flesh samples, which in general had a more diverse microbiota than seeds, stem or calyx", said the researchers.
The results also mirrored findings on fungal communities in apples. "Our results agree remarkably with a recent study on the apple fruit associated fungal community, which revealed specificity of fungal varieties to different tissues and management practices," said Birgit Wasserman, lead author of the study.