Rapid methods for hygiene determination
Hygiene procedures are designed to remove debris and contamination from a previous production run and sanitise equipment prior to starting the next run. Manufacturers must ensure that the established cleaning and sanitation procedures reduce the microbiological, allergenic and residual products to satisfactory level. Additional to this, the cleaning and sanitation solutions used should not leave a residue. The methods for hygiene verification should provide results that allow manufacturers to demonstrate that food safety risks control measures work. These methods must be simple, rapid and robust.
The most popular and established rapid hygiene monitoring techniques are ATP (based on the detection of adenosine triphosphate by bioluminescence) and protein detection. For each, there are kits designed to provide rapid results and to be used by unskilled personnel to assess the effectiveness of the cleaning procedure. However, these techniques can only be used as an indicator of general hygiene as they lack specificity. The ATP techniques detect ATP which is present in a wide range of cells from humans, microorganisms as well as food debris. Protein analysis uses a chemical colour change to detect total protein amount on a surface after cleaning to give an indication of allergen removal. This summary document reviews some of the latest hygiene methods for rapid, specific detection of contaminants to allow manufacturers to prevent and control food safety risks during production. The methods are divided for specific residues (microorganisms, allergens, meat species). The summary document describes the principle of working, strengths, limitations and provides the examples of commercially available kits/systems where applicable.
Optical assays use a broth medium containing unique dyes which indicate metabolic activity as microorganisms grow. Microbial growth is detected by changes in either colour or fluorescence as metabolic processes take place. These changes (expressed as light intensity units) are detected by the optical sensor within the instrument and captured by the computer software for analysis. Various dyes, which are indicators of metabolic activity can be utilised in these systems. Swab samples are placed into pre-filled test vials containing ready to use growth media and indicators for analysis.