Blue Death in Irrigation Water

While Lebanon witnessed its last Cholera outbreak in 1993 with no local transmission documented, we are facing that ancient threat yet again. Almost three decades later, our country scores more and more cases as water tests conducted in several regions confirm the presence of V. cholerae in our sewages.

As food and water are the main causes of contamination, how to grow and eat safe vegetables and fruits on the cusp of a potential endemic?

Cholera is an acute infection implied after the ingestion of Vibrio cholera. This bacterium survives predominantly in water and food and is closely linked to inadequate access to clean water and poor sanitation.

While it can be fatal when developing acute dehydration, it takes between 12 hours and 5 days for a person to manifest symptoms after the ingestion of contaminated food or water. The trick is that the majority of individuals infected with the bacteria develop no symptoms. Their feces enclose the causal agent, however, and could very well be inducing the infection of others for a dozen days.

Throughout the 1800s, cholera sprung from its original reservoir in the Ganges delta in India to the rest of the planet, causing six subsequent pandemics that cost millions of the world’s population. The seventh pandemic, which began in South Asia in 1961, reached Africa in 1971 and the Americas in 1991 as the disease is now endemic in many countries.

Leafy greens are among the products most susceptible to bacterial contamination. This category includes multiple varieties of Lettuce, Arugula, Cabbage, Chard, Endive, Escarole, Kale, and Spinach. The bacterial agents responsible for contamination have been traced to the droppings of nearby livestock or feral animals in the area.

In addition, contaminated Fruits and vegetables are:

• Grown at or near ground level and fertilized with night soil
• Irrigated with water containing human waste or rinsed with contaminated water, and then eaten raw
• Or contaminated during handling, washing and preparation (Cholera Outbreak Response, 2020)

Pathogens and germs that can make people sick or perhaps kill them can be found in irrigation water. There is a chance that these viruses will get onto fruit or vegetables if polluted water comes into direct contact with them.

Produce that has been tainted cannot be harvested, packed, sold, or transported according to international rules. To maintain customer safety, every effort should be made to prevent produce from becoming contaminated with germs.

A useful technique to learn more about the composition of your water is to collect water samples at the pumping station for microbiological testing.

Produce that is ready to eat but has not been prepared before consumption presents a higher risk for food safety and necessitates extra care throughout manufacturing.

According to the Produce Safety Rule of the U.S. Food Safety Modernization Act (FSMA), it is possible to lower the risks to food safety posed by irrigation water of poor quality by setting a delay between irrigation and harvest.

This waiting period is known as the pre-harvest interval, or PHI.

In the US, growers are informed that a 2-day PHI will lower bacterial load to 10% of its original value and a 4-day PHI to 1% of its original value.

However, it cannot be assured how quickly the population will decline. Additionally, other pathogens may or may not die off at the same pace. As a result, it is impossible to predict how long growers must wait after irrigating with contaminated water to ensure the crops are not contaminated.

In Lebanon, assuming that the existing water and sanitation systems are working properly, cholera should die out according to Beigbeder, UNICEF representative in Lebanon.

While the Ministry of health recently revealed the presence of bacteria in the irrigation water for crops in the north of the country, the collapse of water infrastructure endangers the health of millions of people, especially children. So what are the best agricultural practices to keep the produce clean?

The greatest strategy to lessen the risk of microbial contamination, according to AUSVEG, is to keep animals and dung out of irrigation water and crop regions. Additionally, risk can be decreased by employing irrigation techniques that avoid contact with the harvestable area, such as sub-surface drip irrigation, and only applying soil amendments that have been adequately composted.

If the risk from your irrigation water is great, consider mitigating techniques to lower the danger:

• Use a method of irrigation that evades direct contact between water and the fruit, such as drip irrigation or micro sprinklers (under tree)
• Pick an alternative water source.
• Treat water to improve its quality

For more information on the Cholera outbreak and methods of control and prevention, refer to the WHO where all trusted data can be found.

Eng. M. Bou Zeid