Biofilm has been described as a are complex microbial ecosystems formed from one or several microbes bound in a complex extracellular matrix of their own secretions and formations. In earlier discussions in this biofilm series, we have talked about general formation of the complex ecosystems, the detection, classical and modern control methods of biofilms in these ecosystems and the key microbes that make up the ecosystems as well as the potential healthcare impact.
In this part, we will discuss the areas where biofilms in food can original and pose the most public health threat.
Where can biofilms be found in food, food processing and serving environment?
The development of biofilms also depend on the type of factory, machineries, materials used in the various processes as well as the controls in place. Important material determinants may include the source and quality of water, added additives, other liquid pipelines, pasteuriser plates, reverse osmosis membranes, tables, contact surfaces, employee gloves, animal carcasses, storage silos for raw materials and additives, dispensing tubing, packing and packaging material, bottling equipment and even the cleaning and disinfecting agents made available from third party suppliers.
A small single unit food processing plant. Biofilms may develop in any part of the food processing plant or machine part. Eradication may be easy due to less plant complexities.
A multi-unit food processing plant. Biofilms can develop on any part including the conveyor belts. The more complex the machine, the higher the risk of biofilm development and the control process and potential cost. Thorough, robust and regular cleaning regime is necessary.
With poor care strategies, multi-unit automated food processing machines can be attractive ground for biofilms. Biofilms in such environment can be even more challenging to eradicate.
A multimodal control measure should be considered.
Food items whether solid matrix like meat or liquid such as milk kept in refrigerators particularly when over due can be home to biofilms. When contaminated, these items may form films or gel-like materials on the food surfaces, separate into partitions, change in colour and produce repulsive odour due to the bacterial growth. Contaminated items should be discarded and the storage thoroughly cleaned with appropriate disinfectants.
Manual Soap Dispenser: The inside of a manual soap dispenser from a supermarket washroom. The brown spots inside the dispenser white surface are accumulating biofilms and around the metal rings. They have a real potential to contaminate the soap dispensed on to hand
Automatic Soap Dispenser: Bottom end of an automatic soap dispenser taken from a food serving supermarket showing accumulation
Biofilms contamination in food can be from farm or industrial processing sources
Improperly cleaned and/or preserved, processed, pre-cooked, cooked and raw meat, dairy, fruits and vegetable products can be a breeding ground for biofilms leading to food poisoning from secreted toxins.
References
- Bottone, E. J. (2010). Bacillus cereus, a volatile human pathogen. Clin. Microbiol. Rev.23,382–398.doi:10.1128/CMR.00073-09
- European Food Standard Agency (EFSA) Panel on Biological Hazards [BIOHAZ] (2016). Risks for public health related to the presence of Bacillus cereus and other Bacillus spp. including Bacillus thuringiensis in food stuffs. EFSA J. 14: e04524. doi: 10.2903/j.efsa.2016. 4524
- Ehling-Schulz, M., Frenzel, E., and Gohar, M. (2015). Food–bacteria interplay: pathometabolism of emetic Bacillus cereus. Front. Microbiol. 6:704. doi: 10.3389/fmicb. 2015. 00704
- Galié, S. García-Gutiérrez, C. Miguélez, E. M., Villar, C. J. and Felipe Lombó, F. (2018) Biofilms in the Food Industry: Health Aspects and Control Methods F. Microbiol. (2018) Vol. 9, 898, doi: 10.3389/ fmicb.2018.00898
- Gutiérrez, D. Rodríguez-Rubio, L. Martínez, B. Rodríguez, A. and García, P. (2016). Bacteriophages as weapons against bacterial biofilms in the food industry. Front. Microbiol. 7: 825.doi: 10.3389/fmicb.2016.00825
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