According to a new study, in addition to containing fiber and vitamins, an apple also contains about 100 million bacteria, and whether these microbes are good or bad for health can depend on how the fruit was grown.
In general, organic and conventional apples are occupied by a similar number of bacteria.
The study, published in the journal Frontiers in Microbiology , shows that organic apples house a more diverse and balanced bacterial community, which could make them healthier and tastier than conventional apples, as well as better for the environment.
“The bacteria, fungi and viruses in our food temporarily colonize our intestines,” said Professor Gabriele Berg of the University of Technology in Graz, Austria.
“Cooking kills most of these, so raw fruits and vegetables are particularly important sources of intestinal microbes,” Berg said.
ORGANIC APPLES VS. CONVENTIONAL
To help us choose our colonists wisely, the team analyzed the microbiome of one of the world’s favorite fruits: the apple.
“In 2018, 83 million apples were grown and production continues to increase. But while recent studies have mapped their fungal content, less is known about the bacteria in apples, ” said Berg.
The researchers compared the bacteria in conventional apples bought at the store with those of fresh organic visually combined.
The stem, the shell, the meat, the seeds and the calyx, the little piece at the bottom where the flower used to be, were analyzed separately.
In general, organic and conventional apples were occupied by a similar number of bacteria.
“By gathering the averages of each apple component, we estimate that a typical 240 gram apple contains approximately 100 million bacteria,” Berg said.
Most bacteria are found in the seeds, and meat accounts for most of the rest. So, if the nucleus is discarded, the intake drops to almost 10 million, the researchers said.
“Freshly harvested and organically managed apples house a significantly more diverse, more uniform and distinct bacterial community, compared to conventional ones,” Berg said.
“This variety and balance is expected to limit the overgrowth of any species, and previous studies have reported a negative correlation between the abundance of human pathogens and the microbial diversity of fresh produce,” he said.
Specific groups of bacteria known for their potential to affect health also weighed in favor of organic apples.
“ Escherichia-Shigella , a group of bacteria that includes known pathogens, was found in most samples of conventional apples, but none of the organic apples. For the beneficial Lactobacilli , of probiotic fame, the opposite happened, ”said Berg.
“ Methylbacteria , known to improve the biosynthesis of strawberry-flavored compounds, was significantly more abundant in organic apples; “Especially in shell and meat samples, which generally had a more diverse microbiota than seeds, stem or calyx,” he said.
The results reflect the results of mushroom communities in apples, the researchers said.
“Our results are markedly consistent with a recent study on the fungal community associated with apple fruit, which revealed the specificity of fungal varieties to different tissues and management practices,” said Birgit Wasserman, lead author of the study.
Studies show that, through bacteria and fungi, the apple microbiome is more diverse in organically grown fruits, the researchers said.