Apples contain about 100 million bacteria, but organic apples are still good for gut health and the environment

A recent study in Frontiers in Microbiology showed that apples can contain as many as 100 million bacterial cells – and that organic apples contained more beneficial bacteria than conventional or store-bought ones. The study also showed that store-bought apples not only lacked these beneficial bacteria, these also harbored bacteria strains that are known pathogens.

Gut bacteria help improve health and prevent chronic diseases

The human gut microbiome is comprised of trillions of bacteria, fungi and other microscopic organisms. But unlike the pathogenic bacteria that cause infection and disease, these microbes help maintain gut health and protect the gastrointestinal tract from inflammation and other abnormalities.

For instance, common gut problems like indigestion, abdominal cramps and constipation are often due to an imbalance in the gut microbiome. Bacterial communities in the gut also aid immune functions and boost metabolic processes. Studies also suggest that gut bacteria help reduce the amount of “bad” cholesterol in the blood, which increases the risk of heart disease.

Given the different integral functions of gut bacteria, it is important to maintain optimal gut health. To do this, most people consume fermented foods that contain tons of beneficial microbes or probiotics, such as Lactobacillus bulgaricus, Streptococcus thermophilus and Saccharomyces cerevisiae (yeast).

Some fruits like apples, bananas, blueberries and pears are also prized for their probiotics and high fiber content that help boost gut health. (Related: Compounds in citrus fruits and orange juice found to improve gut health.)

Organic apples contain beneficial bacteria

A team of researchers from the Graz University of Technology in Austria found that organic apples harbor a large number of bacteria. But unlike pathogenic genera that cause a host of diseases, these bacteria might benefit gut health.

The researchers used microbial deoxyribonucleic acid (DNA) extraction and gene sequencing technologies to determine the strains of bacteria found in the different parts of the apple. The team used the Arlet apple, a popular variety in Austria, and examined both organic and conventional varieties.

The findings revealed that the seeds, stem, pulp and calyx contained the most number of bacteria. The researchers estimated that each of the eight apples sampled (four per group) contained about 100 million bacteria. And although the seeds are responsible for the distribution of these bacteria, the researchers stated that the plant’s surrounding environment might also be a major source of the microbes.

Moreover, the researchers noted that although the organic and conventional apples harbored the same number of bacteria, the composition of the bacteria differed. Organic apples had a more diverse collection of bacteria that included the beneficial Lactobacillus, a genus of bacteria found in fermented foods like yogurt and pickles.

The peel and pulp, in particular, contained large numbers of Methylobacterium, a type of bacteria used to promote plant growth. Past research has also shown that Methylobacterium can stimulate the flavor compounds in strawberries. Hence, the researchers suggest that this same bacterium might also contribute to the sweeter flavor of the organic apples.

On the other hand, conventional apples had pathogenic genera like Erwinia and Escherichia. Bacteria of the genus Erwinia are often linked to root rot, while Escherichia bacteria are known to cause intestinal infections and diarrhea. The conventional apples also did not contain as much beneficial bacteria as the organic ones.

The researchers suggested that the bacterial diversity in the organic apples might help limit the abundance of pathogens in the human gut. They thus concluded that organic apples provide benefits for the consumers more than the conventional varieties, which were found to harbor food-borne pathogens. Furthermore, the cultivation of organic apples might also be more beneficial to the environment.

Organic apples contain 100 million beneficial bacteria. Although little is known about the bacterial profile of other fruits, it’s best to stick to fresh and organic produce from local grocers and farmers.

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