6. Do either of the subject matter experts have any tips for detection of biofilm that are not visible to the naked eye?
When it comes to biofilm detection there are several different approaches you can take. Which one you take should depend on what you are trying to achieve. For example,
(a) If you are looking to control the level of microorganisms on a surface and would like to know how many, or what type of organisms are present, you can use microbial swabbing. The swabs can be used to sample a surface and then be analyzed to give you the number of microorganisms present (usually expressed per unit surface area, e.g., numbers of microbes per square centimeter), or the number or presence/absence of a particular pathogen. Microbiological swabbing can provide you with quantitative/detailed information on the level/types of microbes present, however, it is expensive and takes time to get the results.
(b) If you are looking to see whether a surface is clean or dirty (even if it appears visibly clean), you can use ATP swabs. A high ATP result will tell you that lots of ‘organic dirt’ (microbes, biofilm, food, etc.) is present, a low result will indicate that it’s relatively clean. ATP swabbing is quick, easy, and relatively cheap to use. It is also widely used and accepted by the food industry. However, because you are looking for ATP (and not specifically microbes) it will depend on whether the ‘dirt’ you are looking for contains ATP in quantities representative of the dirt present. For example, ATP won’t detect viruses on a surface, as they don’t contain ATP.
(c) There are a few chemical spray methods available for biofilm detection, including:
- Biofinder, which works by detecting the catalase enzyme, which is found in many microorganisms, to react with hydrogen peroxide and release bubbles into a gel, and
- TBF 300s Biofilm Spray, which stains the polysaccharide ‘slime’ layer present in biofilms, showing their presence or absence visually.
Both detection technologies are quick, easy, and cost-effective to use as a way of detecting the presence of biofilms/monitoring cleaning. However, Biofinder may also pick up on catalase in some foods and give a false positive result, and neither give you any quantitative data (like microbial swabbing and ATP) or an idea of which microbes are present.
(d) Some auditors also use a UV flashlight, and UV scanning systems are also available, e.g., see video at: https://www.youtube.com/watch?v=_TVLATkrLAM. These systems may help visualize biofilms and allow targeted sanitation approaches.
7. What kind of cleaning method can remove biofilms most efficiently? There are various types of cleaning agents, but what kind of cleaning agent is said to be the most effective?
The most effective cleaning method to use for biofilm removal is mechanical action, i.e., scrubbing, wiping, use of pressured water, etc. However, the most effective approach to biofilm control is to use an appropriate combination of sanitation chemicals (detergents, disinfectants, sanitizers), at the appropriate temperature, together with the appropriate mechanical action, at an appropriate frequency.
The type of sanitation chemicals and mechanical action, and cleaning frequency and temperatures you choose will depend on many things, including, but not limited to:
- the type of food you are producing,
- the type of surface you are disinfecting,
- the standards/regulations you are trying to comply with
Our recommendation for the best course of action would be to speak to your local cleaning chemical supplier and get their advice. In our opinion, the best approach for remediation is to start with a product that has a high dose of surfactants and alkalinity for cleaning and then follow up with a registered biofilm disinfectant.
Remember, biofilms are filled with polysaccharides, proteins, fats, nucleic acids, and minerals, so another important point is to not expect biofilms to be removed after one cleaning. Remediation can take a while.
- First, you need to maximize the removal of the food soil that covers the biofilm in the drain. This is best achieved using the detergent selected for that soil removal on food processing equipment and the environment by the cleaning chemical supplier.
- At a second detergent stage, chlorinated alkaline detergents may be most effective.
8. What is the preferred water temperature for cleaning stainless steel drains?
The temperature of the water you use to clean your drains is important in relation to, at least, three things:
(a) the soils and debris you are trying to remove – If soils are protein-based, hot water could ‘cook’ them onto the surface of the drain and make them more difficult to remove. By contrast, if they are fatty, then hot water will aid removal;
(b) the chemicals you are using to remove soils – Sanitation chemical manufacturers develop their products to work optimally at a given temperature. If you are using a particular sanitation chemical for drain cleaning, you should use it with water at the suggested temperature; and
(c) the materials the drain is made from – Good drainage systems are constructed from materials that are suitably temperature and chemical-resistant. You should speak to your drain provider to find out the temperature range the materials in your drains are capable of withstanding.
Also note that:
-It is usually not necessary to use excessively high-temperature water for cleaning drains. ACO Building Draining recommends knowing the temperature, chemical concentration, and duration of the exposure from the sanitation chemical manufacturers so that ACO can advise on a suitable grade of stainless steel to be specified. Alternatively, by knowing these components of already-installed drains, ACO could suggest a maximum temperature.
-Deciding on the water temperature is also a tricky question. Obviously, the hotter the better, but higher water temperatures can decrease surface tension and aid water’s ability to remove soil. But we would say go as hot as your safety team allows you to, and within the chemical product’s specifications.
-Water temperature has a greater effect if you are trying to melt and remove fatty food residues e.g.,
- Lamb: 113-131˚F
- Beef & Pork: 104-113˚F
- Poultry: >86˚F
- Butter: >86˚F
- Mayonnaise: >86˚F
- Egg & blood: cold
Disclaimer: The responses given to these selected questions are the professional opinions of hygiene experts and are not necessarily endorsements of any of the products and services mentioned. Companies should conduct their own site-specific risk assessment and develop their own hazard controls as part of their food safety plan. For more information and support, please feel free to contact:
- Deb Smith, Vikan Global Hygiene Expert, for biofilm control and drain cleaning queries at dsmith@vikan.com
- Aidan Davey, ACO Building Drainage Regional Specification Manager, for drain selection and management queries at adavey@aco.co.uk