The potential for bacteria to survive cleaning and disinfection means washing routines must be continuously assessed to maintain food safety, according to a scientist.
Thorben O. Reiche, from the Norwegian University of Science and Technology, investigated how bacterial communities in the chicken and salmon industries change when disinfectants are used. His doctoral thesis includes several research articles.
“These types of facilities can harbor bacteria that affect food safety. Some bacteria survive even the strictest hygiene regimens,” he said.
Researchers collected about 1,000 bacterial samples and 100 DNA samples from production facilities for both chicken and salmon in Norway, and for chicken in Romania.
“The results show that cleaning and disinfection are usually effective in reducing bacteria levels. But some areas still had a high prevalence of bacteria, including pathogenic bacteria,” said Reiche.
Biofilm survival
Cleaning reduced bacteria levels by more than 90 per cent, but did not eradicate everything. The potentially pathogenic bacteria found after disinfection included E. coli, Acinetobacter baumannii and Pseudomonas aeruginosa. There were slightly higher levels of bacteria in Romania than in Norway after cleaning and disinfection.
After disinfection, Pseudomonas often dominated, but variations were found between conveyors, processing machines and drains. These bacteria are known to form biofilms that can help other bacteria survive, posing a heightened risk to food safety.
One study provided evidence of biofilms surviving high concentrations of industry-standard disinfectants. Biofilms were significantly reduced by different disinfectants, but survival means they may re-grow under the correct conditions.
Scientists isolated bacteria which can affect the safety of broiler meat, including Listeria monocytogenes, E. coli and Yersinia enterocolitica. While most of these pathogens were detected before cleaning and disinfection, their presence highlights the importance of effective cleaning routines and reliable disinfectants.
None of the disinfectants eradicated all biofilms at the highest recommended concentration, and survival was between 7 and 53 percent depending on the disinfectant.
Researchers said findings highlight the need for targeted cleaning and disinfection routines, considering zone-specific challenges.
“Plant operators should also be aware that biofilms can survive exposure to disinfectants and re-grow under favorable conditions. This can facilitate the persistence of certain bacteria in these environments and increase the risk of food contamination and foodborne disease outbreaks. This suggests that there is a need for disinfectants with stronger biofilm eradication capabilities, potentially in combination with mechanical cleaning,” according to the research report.
Source: FSN
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