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15/06/2021 – Health Series / Hygiene / Cleaning / Covid-19 / Pandemic /Kersia

CLEAN AND CLEAR: Covid-19 impacts on F&B plant cleaning programmes

Exploring the impact that the Covid-19 pandemic has had on cleaning programmes and hygiene practices within the F&B sector, John Holah, Principle Corporate Scientist at Kersia, reflects on lessons learned and ponders the potential benefits that might transpire from such procedural shifts in the future.

Prior to undertaking a cleaning programme for food processing equipment, a number of factors should be considered. Firstly, the objective of the cleaning programme should be determined: This could include the need to remove visual soiling for organoleptic reasons or brand protection issues such as different meat species, the need to control food spoilage micro-organisms, or the need to control hazards such as allergens or pathogens.

Secondly, a risk assessment should be undertaken to assess the choice of cleaning chemicals and application techniques required. This should include the chemical nature of the food soil and the food processing conditions that have led to its formation, the chemical compatibility of the equipment and environmental surface materials, the hardness of the water supply, the application method (manual, automated or CIP), the rinsing method and pressure, and any impact on effluent treatment plants that may be present.

Thirdly, more practical aspects should be considered such as length of cleaning window available and costs. Following these considerations, a cleaning method and chemicals can be chosen that meet the programme’s cleaning objectives, and that have minimal impact on other food processing and environmental activities. 

The current Covid-19 pandemic has done nothing to change these considerations (the original cleaning objective must still be met) and to thus attempt to change current food processing equipment cleaning programmes without due consideration may be counterproductive. In addition, the recommendations from the WHO, CDC and EFSA remain that there is no evidence Covid-19 is transmitted by food or its packaging.

Considering additional hygiene measures

What has changed with Covid-19, however, is the need to consider additional environmental and personal hygiene measures. These are primarily to prevent person-to-person transmission via touching fomites that could have been contaminated from an asymptomatic or pre-symptomatic Covid-19 case. This is particularly important as recent studies have suggested SARS-CoV-2 survival is extended on surfaces, particularly at low temperatures (e.g., a decimal reduction time of 163 hours at 4°C). 

Additional measures have included: 

• Surface disinfection for frequently touched environmental surfaces (e.g., door handles, handrails, light switches, machine interface points) during production

• Surface disinfection for potential virus hotspots (e.g., floors, where expelled droplets will settle and potentially survive)

• More frequent hand hygiene procedures, particularly after touching frequently touched surfaces or viral hotspots (e.g., washing hands after touching the floor or when removing/changing footwear)

• Covid-19 decontamination procedures for food processing and ancillary areas following confirmation of the presence of Covid-19 cases working in these areas.

Do current detergents have an impact?

It may, however, be prudent to ask the question of whether current detergent and disinfectant-based cleaning programmes for food processing equipment have any effect on SARS-CoV-2. One of the lessons we have learnt about the control of Covid-19, that has been well broadcasted to the public, is that “washing your hands with soap and water dissolves the virus”, which is based on established facts. Some detergents may, therefore, influence coronaviruses.


Holchem has commissioned studies to assess the effect of a range of Holchem detergents on coronaviruses with the Perfectus Biomed Group (Daresbury, Cheshire, UK). Six detergents were chosen to reflect the type of detergents commonly used in the food processing and food-service industries, to include caustic, alkaline, neutral and acidic products. The detergents were tested against the human coronavirus strain HCoV-299E using the method of the European virucidal disinfectant test EN 14476, under dirty conditions, according to their recommended concentrations and contact times. 

All of the detergents showed virucidal effects (Table 1), with a range of between 1.5-3.67 log orders of loss of infectivity (96.8-99.98 per cent reduction) within their in-use concentrations. The surfactant-based products were the most effective, within their five-minute contact times, rather than the extended contact times (20 min) of the caustic and acidic products. The acidic product was more effective than the caustic detergents.


Any virucidal activity realised in practice from detergents, however, will be inconsistent and will depend on the level of soiling present on the surface. Detergency, however, will have some role in reducing the presence (removal) and infectivity of (remaining) coronavirus, particularly after much of the soiling present has been removed from the surfaces. However, as disinfection is only ensured following cleaning, this work emphasises the need for disinfection (following detergent application) to further reduce the infectivity of any viral particles present.


As coronaviruses, including SARS-CoV-2, are enveloped viruses, they are the least resistant to disinfectants of the micro-organisms found in food establishments. In addition, the effectiveness of disinfectants on coronaviruses is well documented (e.g., sodium hypochlorite and alcohol, QATS, sodium hypochlorite, hydrogen peroxide and ethanol). Specific disinfectant product performance claims can be made for virucidal activity against the European disinfectant test, EN 14476, which requires a 4-log reduction of infective viral particles in five min. Disinfectants used for additional environmental decontamination (as advocated above) and decontamination following any known Covid-19 cases, must be EN14476 approved.

Have Covid controls brought additional advantages?

Holistically, the detergency studies and general knowledge on viral disinfection enhance our knowledge of the overall potential of routine processing equipment cleaning and disinfection programmes to meet their established cleaning objectives, while providing additional assurance that they are also controlling SARS-CoV-2.


Looking to the future, hopefully, the additional practices the food industry has undertaken associated with environmental surface disinfection and enhanced hand hygiene have helped in their intended Covid-19 control. Collectively, these measures perhaps represent the biggest change in hygiene practices within the food industry for many years. Is it possible that these changes could also have brought additional benefits in terms of food safety or personal health? Fewer micro-organisms in the food process environment (including operatives’ hands) might lead to reduced levels of general micro-organism indicators (TVC, Enterobacteriaceae) and reduced levels of environmental pathogens (particularly Listeria) via cross contamination in food products. This could lead to enhanced product safety, quality (reduced spoilage), improvements in shelf life and fewer customer complaints. Fewer other, non-SARS-CoV-2, respiratory viruses on operatives’ hands could also lead to fewer cases of respiratory diseases (colds and flu), resulting in less absenteeism. 

Is there any evidence of enhanced food safety? In the wider community, Public Health England published cumulative data up to week 30 for common gastrointestinal infections in England and Wales (Table 2). Table 2 shows that the general incidence of gastrointestinal infections in the population was approximately one-third lower in 2020. Similarly, the number of Listeria recalls alerted by the UK Food Standards Agency (FSA) in 2020 (six cases) was slightly lower than in 2019 (seven cases). This position is not unique to the UK as other countries have also shown a reduction in pathogen incidence in the community, including in Finland, the USA and Australia.


The reasons for the reduction in cases of gastrointestinal illness in the population is complex. Perhaps not as many cases of illness have been reported due to difficulty in accessing GPs, or people are not eating outside the home in restaurants so much, or the diet of people spending more time at home has changed. There may also be changes in the food factory or the manufacturing procedures that might enhance food hygiene – for example, reduced food product volumes, fewer product SKUs, fewer staff, increased use of gloves, and longer hygiene windows to enable enhanced cleaning. Equally, the opposite may be true, with food manufacturers increasing production, particularly at the start of the pandemic, with an increased pressure on maintaining hygiene windows.


It would be very useful, therefore, for both individual food manufacturers and the industry at large to try and gain evidence from food industry data to see if these major changes in food hygiene practices have had additional benefits to food safety or personal health. Perhaps the biggest lesson that we have learned is that the higher the hygiene standards practised, the greater the food safety benefits. In essence, should our current, extended cleaning and disinfection practices become the new, post-Covid-19 pandemic, norm?

About the author

John Holah is Principal Corporate Scientist for Food Safety and Public Health at Kersia Group ( He was Technical Director at Holchem Laboratories Ltd prior to the acquisition of Holchem by Kersia, and before that was Head of Food Hygiene at Campden BRI for more than 20 years. 

An Honorary Professor in Food Safety and Hygienic Design at Cardiff Metropolitan University, John has supported the works of the European Hygienic Engineering Design Group (EHEDG), the International Association of Food Protection (IAFP) and the Global Food Safety Initiative (GFSI) for many years. He has chaired various ISO and CEN committees on hygienic design and chemical disinfection, and has sat on government committees on food safety and hospital acquired infections.

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