The Massive Impact of Irrigation Water
As consumers we care most about the tail end of the trickle-down impact irrigation water has. We hear about contaminated produce being served to customers, like the Salmonella contaminated lettuce served to Subway customers in Illinois in 2010, or cucumbers being recalled from major grocery stores in Western Canada in 2015, again for risk of Salmonella contamination. But how do these contaminations occur?
Microorganisms that cause food poisoning are not naturally occurring in fresh fruit and vegetables, but there are many ways in which they can be introduced. Before we get into the sources of contamination, let’s talk a little about what contaminants are and where they originate.
In North America, the most common food poisoning causing bacteria are E. coli, Listeria, and Salmonella.
Starting with one bacterium we are more than familiar with in our lab, E. coli has many strains, most of which are harmless to humans. However, pathogenic strains can cause a variety of health issues, including gastric problems, urinary issues, respiratory illness and more. E. coli is a fecal coliform, meaning it originates in the lower intestinal tract of humans and animals. Although some strains of E. coli are beneficial to our gut flora, the presence of any strain in water is a clear indication of contamination from fecal material and therefore has no business having any contact with food.
Listeria monocytogenes is a bacterium that can cause Listeriosis, an infection of Listeria that has moved beyond the intestinal tract. It is commonly found in soil, water and the feces of animals. Listeria infection risk is the reason pregnant persons are advised to avoid soft cheeses, deli meats and delicious sushi, as infection can come with a whole host of health concerns. Pregnant people are not the only ones at risk, but they are 10 times more likely to contract an infection than anyone else, and a severe infection can lead to miscarriages, stillbirths and other alarming issues.
Salmonella is probably the most well-known contaminant in our list. We’ve all been taught to avoid eating raw chicken, but the risk can be present on your produce as well. Like E. coli, Salmonella is a bacterium that lives in the intestinal tract of humans and animals and can be present in the surrounding environment. It also has a myriad of complications involved with infection, most notably gastric upset, but in more severe cases can lead to typhoid fever or paratyphoid fever. It should also be noted that Salmonella is becoming increasingly resistant to essential antibiotics needed to treat severe cases.
Now that we know a little more about what could be living on our fruits and vegetables, what does this all have to do with irrigation water? Let’s move through the stages our food typically goes through before it ends up in our homes. According to Statista, 87% of Canadians get their groceries from supermarkets, so for our example this will be the path we will demonstrate.
Before harvesting, your produce is under the care of the farm it is grown on. This is where our chain of possible contamination originates. The bacteria on our list of common causes of food poisoning can all potentially thrive through agriculture, specifically in water and soil. In a perfect world all of our produce would be cultivated through rain-fed agriculture. This would lesson contamination risk to food products, but irregular weather patterns and drought often requires supplementation with a man-made irrigation system. This is where some problems can come in. Every irrigation system requires a water source, and in agricultural areas, contaminated water is a constant concern. Waste from livestock, poor sanitation and aging septic systems are all potential causes for contamination in irrigation water.
Imagine a farm that specializes in growing lettuce for consumer distribution, but also maintains a small amount of dairy cattle. Our lettuce farm uses a center pivot irrigation system that draws water from a well on the property that is located near the cattle pens, which has been collecting run-off from the manure compost for a number of years. Since the well isn’t used for drinking water, testing has been overlooked for some time and believed to be of no consequence.
Fecal bacteria has now made its way from the well, through the irrigation system and is now living on the lettuce. After harvesting, the lettuce is sent in large loads to a packaging centre that serves our farm and several other produce farms in the area. Contaminated water that exists on our lettuce has now made contact with several pieces of equipment both during transportation to the facility and as it makes its way through packaging. This in turn has potentially contaminated produce from farms that do test their irrigation water and considered their produce to be safe.
After packaging, our contaminated lettuce is now being shipped to distribution centres across North America. Here it is stacked on pallets with more produce, set to be distributed to grocery stores and processing centres. Contaminated water droplets seep from holes in the packaging, dripping between the cardboard cases to more produce.
Our lettuce that was sent to a processing centre for use in pre-packaged salads is briefly rinsed. The brief rinse has helped to remove some of the bacteria, but not enough of it. The lettuce is now chopped and added to containers with other ingredients to make pre-packaged salads and then shipped to grocery stores.
The rest of the lettuce is now received by your local supermarket and stocked in the produce section, waiting for you to purchase it for your family. From here, it’s easy to see how potential outbreaks can occur. From the situation presented, the lettuce you’ve purchased that’s now being used for your salads, your kid’s sandwiches and as a garnish for taco night could easily be harboring any of the contaminates listed earlier.
Now imagine the same scenario, however our farmer took advantage of our Advanced Irrigation Suitability package. This would have alerted our farmer that the water source they drew from had fecal coliforms present, making it unacceptable for food production, and informing the farmer of the contamination risk. From this one simple test, an entire chain of potential outbreak could have been mitigated.
Testing for potential contamination isn’t the only thing testing irrigation water is important for. This same test alerts you about heavy metals in the water that could be absorbed into the soil and crops, the pH level, and if there are already essential nutrients in the water that could save you from needing supplemental fertilizer.
Our packages are designed for affordability, rapid test results and accuracy. Our sampling process is simple and our staff is here to walk you through every step. If you need your water tested, please take a look at our packages. We have tests designed to meet whatever your needs may be.
References:
Centers for Disease Control and Prevention – Types of Agricultural Water Use
Food Safety News – “Subway Apologizes to Salmonella Outbreak Victims” by Alexa Nameth
Government of Canada – Produce Safety
Food Safety – Bacteria and Viruses
Centers for Disease Control and Prevention – Salmonella
Centers for Disease Control and Prevention – Listeria (Listeriosis)
Centers for Disease Control and Prevention – E. coli (Escherichia coli)
Supermarkets and grocery stores in Canada – statistics & facts