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By: Bill Rufenacht | Technical Specialist, Dairy Connection Inc.   

Proper sanitation of food contact surfaces and equipment is important to all of us producing food products. The last thing we want is to make a product that spoils quickly or worse, makes someone ill. As a result, we spend nearly as much time cleaning and sanitizing as we do actually making our products. 

Most dairy soils are stubborn and can be difficult to remove completely. Fat, protein, and water-soluble materials make up most dairy soils. Chemicals used to remove these soils are powerful and specific to these soils. Consulting a chemical supplier familiar with dairy soils, getting their advice for an effective chemical selection and a sanitation program is important to produce safe food. These suppliers can be a very valuable resource for you.

But how do you know your food surface is clean? We can observe that rinse water will flow off a clean stainless surface in sheets. If we see rinse water beading up on a cleaned stainless-steel surface, we know that there is likely some fat remaining. Similarly, if we notice a blue or purple sheen on stainless after cleaning, we can assume there is some protein soil building up. Unfortunately, it is not possible to look at any equipment surface and determine if it is clean in a microbiological sense

Microbiological sampling (swabbing for specific pathogenic or spoilage organisms) and testing is the surest method to verify that your equipment is clean. This testing is relatively expensive, requires a trained person to collect samples, specialized equipment and materials, is typically run off-site at a lab, and results take hours or days to achieve. Though unquestionably a valuable tool in your quality control arsenal, the cost and time involved make microbiological sampling for specific pathogenic- and spoilage-causing organisms a cumbersome choice to verify sanitation on a daily basis.

As another option, tests have been developed to detect residual protein on surfaces. Residual protein indicates that your surfaces are not completely clean, and that soil which can support the growth of spoilage or pathogenic organisms may be present. This type of test does not indicate the presence of these organisms per se, only that conditions exists for undesirable organisms to be present and grow.  PRO-Clean™ by Hygiena is an example of this type of residual protein test. It is a simple test requiring no special equipment other than the self-contained, shelf-stable swabs. It is a relatively inexpensive test, and rapid enough to be useful in verifying sanitation as a pre-production or post-cleaning method.

Hygiena PRO-Clean™ Rapid Protein Residue Test

This detection method is designed for testing a surface after cleaning. PRO-Clean™ will turn from green to purple if protein is present in a sample. The greater the amount of protein, the deeper and more quickly the color will change to purple. The test is designed to be conducted at room temperature – there is no need to incubate the swabs. A video demonstration can be viewed below:

Hygiena sells their protein residue test in cases of 100 swabs. Dairy Connection plans to make these swabs available for purchase soon in smaller-than-case quantities to clients interested in performing this type of verification of cleaning. Please watch our website for price and availability, and don’t hesitate to contact our technical team for more information.    

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