In a banana, the phloem strands are therefore the reason why all the nutrients can reach the whole of the fruit - which allows it to grow into the fruit we know of.
Nicholas D. Gillitt, who is vice president of nutrition research and director at the Dole Nutrition Institute explained to Huffington Post: "Phloem bundles are necessary for the adequate disposition of nutrients throughout the plant."
The phloem bundles are completely edible and are just as nutritionally rich as the main part of the fruit, according to Dr Gillitt.
In fact, the strands probably contain a lot more fibre than the rest of the fruit, he says.
It is possible to genetically modify the fruit to prevent strands from forming - but Gillitt says there is little point dedicating funds to research this when companies can better invest in coming up with disease-resistant food or fruit with higher nutritional content.