We couldn’t agree more with Gordon Ramsay. Hygiene in commercial kitchens is of high importance, and we wrote a 2-part blog post on the subject in our sister hygiene blog: Insights. A commercial kitchen is not the environment in which one would ever want to see pests (we wrote a blog about that too), especially not flies. Fly species are carriers of a host of serious illnesses, including typhoid fever, cholera, conjunctivitis, tuberculosis, and diarrhoea – one of the main reasons to prevent flies in your restaurant kitchen.
What draws flies to a kitchen?
There are a number of things that can lure flies into your restaurant kitchen, but the main attraction is food. This can be the food you are preparing for your guests or food in the form of waste and spills. But did you know that the grease and sludge in your grease trap are also hugely attractive to flies and other pests? It’s like inviting them to an all-you-can-eat, 24/7 buffet.
What is a grease trap?

A grease trap is a plumbing device designed to slow down the flow of greasy wastewater. It separates out grease and solid waste before they enter the sewerage system.
The water flows down the pipe to the sewer, and the grease floats to the top and is retained in the trap. The design has remained largely the same since they were invented in Victorian times, and they still utilise the same laws of physics: grease and oil are lighter than water and rise to the top when the mix is allowed to stand.
Why do commercial kitchens need grease traps?
The South African sewer reticulation system is only geared to accept toilet, sink, basin, and bath waste. Our stormwater system is only geared to accept rainwater. Anything else puts a severe strain on the system and ultimately causes blockages.
Commercial and restaurant kitchens produce large volumes of waste grease, present in the drain lines from various sinks, dishwashers, and cooking equipment. The law requires that all premises engaged in the cooking and preparation of food must install and maintain an adequately sized grease trap.
What happens to the waste?
So what happens to the fats, oils, grease and starch (FOGS) that are separated by the grease trap and prevented from entering the wastewater system? These form a scummy layer in the grease trap which must be disposed of regularly. If the grease trap is not regularly cleaned out, the accumulation of FOGs and foodstuffs can start to rot and give off the characteristic rotten egg drain smell. This rotting sludge is extremely attractive to pests such as flies and cockroaches – a veritable buffet – and a common cause of flies in your restaurant kitchen.
Grease trap maintenance:
It is the kitchen occupier’s responsibility to ensure the proper maintenance of their grease trap. Biological Dosing offered as part of Initial’s CaterClean service or as a stand-alone service – is an environmentally friendly, non-chemical maintenance program for grease traps. The biological enzyme, which is dispensed into the system in a metered-dose, digests FOGS, thereby eliminating blockages. Installed, serviced and maintained by Initial, bio-dosing results in a free-flowing drainage system.
How can a clean grease trap prevent flies in your restaurant kitchen?
Initial’s bio-dosing unit pumps a measured dose of bio-enzymes into the grease trap. This starts a biological process which digests and liquefies solid organic waste including oils, grease and fat. Organic waste remains free-flowing, and the quality of the effluent released into the municipal sewerage system is improved.
Importantly, pest problems are eliminated by reducing the available food source, and the elimination of bacteria means that the characteristic “bad drain” smell is controlled.
Initial offers 2 types of bio-dosing unit. The type 1 pump is installed internally into wastewater pipes, whilst type 2 pumps are installed on outdoor grease traps. These are usually located at the back receiving area of restaurants, where wastewater exits the kitchen. Units are serviced regularly and after-hours services are available for busy restaurants.
When aiming for a spotless kitchen, remember that your dirty grease trap could be attracting pests. Contact Initial for more information on our bio-dosing service. Contact Rentokil for more information on what else you can do to combat flies in your restaurant kitchen.
Why choose Rentokil Initial for grease trap maintenance?
Regular maintenance of your grease trap is not just a legal requirement, but a key step in ensuring a clean, hygienic kitchen environment free from pests. Investing in biological dosing services from Initial helps mitigate fly infestations, prevents costly plumbing issues, and ensures compliance with South African health and safety regulations. Don’t let a neglected grease trap attract unwanted pests – contact Initial today to learn more about our expert grease trap solutions and ensure your kitchen remains pest-free.
*Legislative Requirements for the Maintenance of Grease traps:
The General Hygiene Requirements for Food Premises and the Transport of Food (R.918/1999) corrected by Govt notice No 638 of 22 June 2018 specify that food premises must have a wastewater disposal system approved of by the local authority and that the duties of a person in charge of food premises include ensuring that wastewater on the food premise is disposed of to the satisfaction of the local authority.
**Western Cape Provincial Wastewater By-Law: 1 Sep 2006. Section 3: Protection of Municipal Sewers
No person shall discharge, permit to enter or put into any municipal sewer –
– any petrol, oil, greases, waxes, fat or pesticides, insecticides or paints
– any liquid that has a pH value of less than 5,5 or greater than 12

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