A new study shows that a typical apple supports more than 100 million bacteria, many of which play a vital role in supporting a healthy gut environment.
The study, by researchers at Graz University of Technology in Austria, also shows that organic apples contain a more diverse and balanced bacterial community than their conventionally grown counterparts.
The researchers compared the bacteria in conventional store-bought apples with those in visually matched organic ones. Overall, the organic and conventional apples were occupied by similar numbers of bacteria.
100 million bacteria
“Putting together the averages for each apple component, we estimate a typical 240g apple contains roughly 100 million bacteria,” says professor Gabriele Berg, one of the authors of the study.
The researchers discovered that the majority of the bacteria are in the seeds, with the flesh accounting for most of the remainder. So, if you discard the core your intake falls to nearer 10 million. The question is: are these bacteria good for you?
“When it comes to gut health, variety is the spice of life – and in this regard, organic apples seem to have the edge,” says Berg.
“Freshly harvested, organically managed apples harbour a significantly more diverse, more even and distinct bacterial community, compared to conventional ones.”
Health potential
Specific groups of bacteria known for health-affecting potential also weighed in favour of organic apples, say the researchers.
“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.”
And there may be further evidence to support the claim of many, that they can “taste the difference” in organic produce.
“Methylobacterium, known to enhance the biosynthesis of strawberry flavour compounds, was significantly more abundant in organic apples; here especially on peel and flesh samples, which in general had a more diverse microbiota than seeds, stem or calyx.”
“The microbiome and antioxidant profiles of fresh produce may one day become standard nutritional information, displayed alongside macronutrients, vitamins and minerals to guide consumers”
The results mirror 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,” comments Birgit Wasserman, Berg protégé and lead author of the study.
Together the studies show that across both bacteria and fungi, the apple microbiome is more diverse in organically grown fruits.
“The microbiome and antioxidant profiles of fresh produce may one day become standard nutritional information, displayed alongside macronutrients, vitamins and minerals to guide consumers,” suggests Wasserman. “Here, a key step will be to confirm to what extent diversity in the food microbiome translates to gut microbial diversity and improved health outcomes.”
Photo by Andrii Podilnyk on Unsplash