Food hygiene myths that still circulate
Listeria in drains, technical-grade gas, the wrong test strips and cheap sanitation: common misconceptions and what to do instead.
Some misconceptions refuse to go away. Here are the ones our auditors and trainers come across most.
Q: "Wet factories always find Listeria in drains. It's not a big deal." True?
False. After effective cleaning and disinfection, you shouldn't be finding Listeria. It can enter on the foods you handle, but once product has been through a removal or kill step, the environment must not contaminate it. If that means cleaning more often or more aggressively, that's the price.
"Clean enough" depends on your product. Washed potatoes that the consumer will wash or process again don't need a high-care environment, and your HACCP and environmental monitoring risk assessment should say so. For high-risk ready-to-eat products there should be no Listeria in the environment, and if you find it, act, document and trend it. Listeria is deadly. Our BRCGS Environmental Monitoring course covers designing and acting on a monitoring programme.
Q: How do we control Listeria?
Stay on top of cleaning and sanitation, keep strict temperature control, use equipment that's easy to clean, test regularly, separate raw from ready-to-eat, and manage drains and water. If you get a positive, act fast to clean and find the cause.
Q: "Technical-grade gas is the same purity as food grade, just cheaper." True?
False. Food-grade status is more than purity on a certificate of analysis. It also covers the grade of the tank steel, filling conditions, valve materials and other factors the supplier controls. Our auditors have raised NCs for technical-grade gas used to flush packaged food. In BRCGS Food Safety Issue 9, gases in contact with product are covered in section 4.5 (utilities).
Q: Can we cut sanitation costs without losing effectiveness?
Target your highest-risk areas first (ready-to-eat zones, hard-to-clean equipment), consider combining or rotating sanitisers, train staff to apply methods properly, and use testing and audits to fine-tune so you're not overspending. Cleaning of premises and equipment (4.11.1) is one of the most common Issue 9 non-conformities, so cut costs with care.
Q: The strangest gap between procedure and reality?
A well-meaning admin colleague found a cheaper supplier of pH test strips. The tester noticed every strip gave the same result: they were urine infection test strips. The lesson: make sure everyone involved in purchasing understands the specification and its purpose.
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Reviewed by Chisala Ngandwe, Technical Manager & Trainer, STC · November 2026
These Q&As share general best practice from our trainers and auditors. They aren't consultancy advice for your site. For support specific to your site and systems, we can refer you to our sister company QTC.
Learn more: Environmental Monitoring, Cleaning Technology & Control Level 3 and the course calendar.