Listeriosis – The Precautions You Should Be Taking, Tips & Symptoms

By now we all know that we have a big problem, but I think many do not realize the scope of the Listeriosis outbreak. Across South Africa, the outbreak of the food-borne disease has been reported as possibly being the largest outbreak of its kind the world has ever seen. This disease has already claimed more than 170 lives. According to The National Health Laboratory Service, 915 cases of Listeria have been reported since January 2017. Those most vulnerable are young people, the elderly and those with compromised immune systems.

Here’s the thing, throwing out your polony, cold meats and viennas is not the only precaution you should be taking. While Enterprise is taking the brunt as the source of the epidemic, it is crucial that we educate ourselves about the other sources of the disease. In addition to polony, cold meats and viennas, the South African government has advised that listeria can also be found in the following products:

  • refrigerated meat spreads
  • unpasteurized (raw) milk and dairy products
  • soft cheeses made with unpasteurized milk
  • refrigerated smoked seafood
  • unwashed vegetables or fruit that are grown in, or have come into contact with, soil and fertilisers.

What a terrifying thought…  what is left that is safe? How do we prevent this outbreak from entering our own homes?

John J Coetzee, CEO at Green Worx Cleaning Solutions states; “It is pivotal that we take proper care in cleaning our foods, particularly fresh produce. The Listeria monocytogenes bacterium is found in the water and soil and can contaminate the foods we eat, either through the soil or from manure used as fertiliser. The best defence against this outbreak is to make sure that everything that goes through your kitchen is cleaned and disinfected.” 

We need to be extra careful, as Listeria is not a disease that is immediately identified.

It has a three-week incubation period which makes recognition of contamination difficult. Coetzee explains that livestock can carry the bacterium unnoticed, leading to contamination of foods of animal origin such as meats and dairy products.

“Listeria comes about via a biofilm which is created by an accumulation of bacteria that develop a protective matrix made up of organic polymers (EPS): polysaccharides and proteins. It is this organic matrix which is very difficult or even impossible to remove using conventional cleaning and disinfection protocols. However, biofilms are the dominant environment for microorganisms. One thousand to 10 000 times more bacteria grow in a biofilm compared to in a planktonic (free) state. Furthermore, bacteria encased in a biofilm can be 1 000 times more resistant to disinfectants (biocides) than planktonic bacteria. To ensure optimal hygiene levels, it is therefore necessary to eliminate these biofilms,” continues Coetzee.

Due to the existence of the biofilm it is not enough to only use disinfectants, as these disinfectants are ineffective against the biofilm bacteria’s organic matrix. It is, therefore, necessary to use products that can degrade the organic matrix in conjunction with a disinfectant. Odorite Ultra Enzymatic Deep Clean 30 x, for example, is currently the only product in South Africa that is effective in this process. “According to the Directorate of Food Control, Odorite Deep Clean Enzymatic is the only enzyme product on the market that is SABS 1828 approved for the purpose of cleaning hard surfaces and CIP in food industries,” adds Coetzee.

“It is necessary to use a complex and highly specific enzymatic cocktail to achieve the destruction of the biofilm matrix. This eradicates the protective biofilm matrix. Conventional cleaning is not able to degrade this matrix. Once the protective matrix has been eliminated, the bacteria are left without any protection. A disinfection phase is then applied to destroy the bacteria which has become planktonic and, therefore, accessible to disinfectants (biocides),” explains Coetzee.

According to scientific expert, Coghan (2016), enzyme-based detergents are used to improve the efficacy of disinfectants against bacterial biofilms. Enzymes can target cells in the biofilm matrix and can cause the matrix to become looser and break up. They can also trigger cell release actions in the biofilm enveloped cells, causing many cells to break off from the biofilm. Enzymes have some role in targeting the bacterial cells encased within a biofilm.

The main function of enzymes is to degrade the lipid, carbohydrate and DNA components of the extracellular matrix, severing the links between cells and subsequently separating them, allowing rapid deterioration of the biofilm integrity. Disinfectants can then act more powerfully to kill cells that were once embedded in the matrix of the biofilm EPS and can also target released cells which have been forced into the planktonic state by the enzymes action.

“Using a product to wash fresh produce that can break down the biofilm matrix, together with a disinfectant, is the best weapon against the Listeria outbreak. This, combined with the effective sanitation of any areas where food is prepared (residentially or commercially) will have a positive impact on the fight against listeriosis,” concludes Coetzee.

In short (+ some extra advice from the Centers of Disease Control and Prevention…

  • Avoid eating soft cheese, such as brie, Camembert, blue-veined, or feta, unless it is labeled as made with pasteurized milk.
  • Only consume pasteurized milk and milk products, including ice cream, cheese and yogurt. Look for the word “pasteurized” on the label. If in doubt, don’t buy it! Make sure the label says, “Made with pasteurized milk.”
  • Do not eat refrigerated smoked seafood unless it is canned or shelf-stable or it is in a cooked dish, such as a casserole.
  • Do not eat refrigerated pâté or meat spreads from a deli or meat counter or from the refrigerated section of a store
  • Avoid eating hot dogs, lunch meats, cold cuts, other deli meats (such as ham), or fermented or dry sausages unless they have been boiled or steaming hot just before serving
  • Do not eat raw or lightly cooked sprouts of any kind (including alfalfa, clover, radish, and mung bean sprouts).
  • Rinse raw produce thoroughly under running tap water before eating.
  • Thoroughly cook raw food from animal sources, such as meat, poultry, or seafood to a safe internal temperature.
  • Wash hands, knives, countertops, and cutting boards immediately after handling and preparing uncooked foods.

Symptoms to look out for:

  • Fever
  • stiff neck
  • confusion
  • weakness
  • vomiting
  • diarrhea


If you are very ill with fever or stiff neck, consult your doctor immediately. Antibiotics given promptly can cure the infection and, in pregnant women, can prevent infection of the fetus.


Green Worx Cleaning Solutions is ISO 14001, Global GreenTag, SABS and Green Building Council of South Africa (GBSCA) certified and supplies innovative, environmentally responsible, biotechnology products based on the use of natural microbes and enzymes. In such, Green Worx supplies green cleaning and sanitation consulting and solutions, pollution control and environmental remediation products to industrial and commercial entities, as well as to consumers. Green Worx prides itself on its associations with global leaders providing innovative, effective and high-quality products and solutions to meet specific customer needs.


In 2016 Green Worx was presented with the Award for runner up in the Green Technology Innovation category of the Mail & Guardian (M&G) Greening the Future Awards. In the same year, the company won the 2016 South African Frost & Sullivan Award for New Product Innovation. In 2017, Green Worx won the “Green Business Award” at the Mauritian African Leadership Awards, and was declared a finalist in both the Sustainability Blank Canvas and Management of Systems awards categories, in The Da Vinci tt100 Business Innovation Awards Programme.


Contact Green Worx on 011 708 6626, at info@green-worxcs.co.za or visit


2 thoughts on “Listeriosis – The Precautions You Should Be Taking, Tips & Symptoms

  1. Kirsten says:

    I’m pregnant at the moment so even though I’m careful with what I eat, now I’m being super extra careful. Thanks for the info – didn’t realise it was unpasteurized food as well !

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