Organic fruits and vegetables contaminated with “extremely harmful” bacteria, a study finds

More than 50 types of harmful bacteria have been found on samples of organic spinach and lettuce, some of which can cause serious health problems like pneumonia and gastrointestinal disorders, according to a Spanish study

Organic vegetables are often contaminated with harmful disease-causing bacteria, a new study warns.

Scientists say people who buy products that have been treated with organic fertilizers like manure may regret their choice for a long time.

More than 50 species of potentially harmful bacteria have been identified on samples of organic spinach and lettuce.

Organic fruits and vegetables are becoming increasingly popular as more people adopt healthy diets and avoid pesticides, fertilizers and herbicides.

But now scientists in Spain have found they could be contaminated with harmful bacteria from human or animal sources.

These are likely to be transferred to vegetables during growth, harvesting, transportation, processing and handling.

Vegetables in particular can contain unicellular organisms such as free-living amoebas (FLA) that feed on bacteria, some of which can be extremely harmful to humans.

These nasty bacteria, called Trojan horses, resist the body’s digestion and pose a serious threat to anyone who eats them.

dr Yolanda Moreno from the Universitat Politècnica de Valencia said: “Food and food environments create an ideal meeting place for free-living amoebas and pathogenic bacteria.

“However, comparatively little is known about the occurrence and diversity of free-living amoebas on organic vegetables and their role in the transmission of human pathogens.”

Lettuce and spinach samples were collected from local supermarkets in Valencia between November 2020 and May 2021.

A special scientific technique was then used to identify the DNA of all the bacteria found in the amoeba.

The main bacterial species identified were Flavobacterium and Pseudomonas, which do not generally cause disease in humans.

However, 52 types of harmful bacteria were detected in a third of the samples, including Legionella, Salmonella and Arcobacter.

These can cause serious illnesses such as pneumonia and gastrointestinal disorders.

Another species called Vermamoeba vermiformis, which often causes severe infections, was found in a fifth of the vegetable samples.

Acanthamoeba castellanii, a bacterium that can cause blindness and encephalitis, was also detected in nearly two-thirds of the samples — 63 percent.

dr Moreno said: “The presence of bacteria of public health importance contained in the free-living amoeba suggests that they are vehicles that can easily transmit pathogens that reach and through humans.” contaminated organic vegetables can cause health problems.

“Contamination can result from treating the soil with organic fertilizers such as manure and sewage sludge, as well as from irrigation water.”

Larger studies from different countries are needed to learn more about the quality and safety of organic vegetables.

dr Moreno said: “Leafy greens are particularly vulnerable to fecal contamination due to their proximity to the ground and the likelihood of people consuming them without cooking.

“Our findings also underscore the need to educate the public about the safe and proper handling of fresh organic vegetables before they are consumed fresh or lightly cooked.”

The results were to be presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) in Lisbon, Portugal.