In today’s quick-fix health economy where we want instant solutions to a myriad of lifestyle-related complaints, it is good news to hear that eating just one apple per day may deliver as many as 100 million bacteria, most of which are contributing to gut stability and overall health.

Positive bacteria found inside apple cells

More interesting still is that research, conducted by a leading science news source, Frontiers in Microbiology, suggests that conventionally and organically-grown fruit are both in different ways healthy to humans.

What’s more is that the fruit skin seems to contain the least amount of positive bacteria. This makes the individual choice to peel, or not, before consumption less relevant.

If you thought these positive bacteria can be washed off, think again. The bacteria are inside the plant cell and not on the outside.

Analysing the apple microbiome

According to Frontiers in Microbiology, while apples are among the most consumed fruit worldwide, they represent a source of bacterial communities which is less studied in terms of direct human exposure. “We analysed the apple microbiome to detect differences between tissues and the impact of organic and conventional management. We used a combined approach of 16S rRNA gene amplicon analysis and qPCR, and visualisation using fluorescence in situ hybridisation and confocal laser scanning microscopy (FISH-CLSM).”

Each apple harbours different tissues (stem, peel, fruit pulp, seeds, and calyx), which were colonised by distinct bacterial communities. Interestingly, fruit pulp and seeds were bacterial hot spots, while the peel was less colonised.

In all, approximately 108 16S rRNA bacterial gene copy numbers were determined in each apple.

Health-affecting bacteria and conventionally managed apples

Abundances were not influenced by management practices. However, a strong reduction in bacterial diversity and evenness in conventionally managed apples were found.

In addition, despite the similar structure, in general dominated by Proteobacteria (80%), Bacteroidetes (9%), Actinobacteria (5%), and Firmicutes (3%), a significant shift of almost 40% in bacterial genera and orders was monitored.

Among them, especially bacterial signatures known for their health-affecting potential were found to be enhanced in conventionally managed apples.

The results suggest that roughly 100 million bacterial cells are consumed with one apple. Although this amount was the same, the bacterial composition was significantly different in conventionally and organically produced apples.

An important source for gut microbes

Tru-Cape Fruit Marketing is the largest exporter of South African apples and pears. Biologist and Tru-Cape’s quality assurance manager, Henk Griessel, says they export Tru-Cape apples to more than 104 countries. Any news that increases the positive demand for apples and pears is therefore good news.

“The article, which included fruit from the Ceres region, explains that the plant-gut microbiome axis could be of special importance for human health.

“The study suggests that eating raw plants are seemingly an important source for microbes and that plant-associated microbiota, including bacteria, fungi and viruses, transiently colonised the gut, which forms our transient microbiome,” concluded Griessel. – Press release, Tru-Cape Fruit