The polyurethane advantage
upgrade to a better sponge and swab
Sponges have been used for over 40 years to sample a diverse range of surfaces in the food production environment from beef, pork and poultry carcasses to production floors, ceilings, drains, and equipment. New polyurethane (PUR) sponges offer several distinct advantages over traditional cellulose sponges as well as wound, fiber-tipped swabs including resistance to tearing, flaking or fraying during sample collection and improved release of organisms for more accurate test results. Additionally, the synthetic manufacturing process of the polyurethane yields a more consistent biocide-free material without any components that may interfere with downstream test methods.
Biocide-Free Material
World Bioproducts’ polyurethane sponges are non-toxic and free of biocides. Unlike the “wet” cellulose manufacturing process, there is no need to include chemicals such as quaternary ammonium compounds to control microbial growth during the polymerization process to produce polyurethane sponges. Additionally, inadequate or inconsistent washing during the cellulose sponge manufacturing process, can result in sponges that are highly acidic (pH 4-5) or basic (pH >10). The water used to wash the sponges can be a source of chloro-ogranic compounds as well as heavy metals.
These factors and others can combine to have adverse effects on microbial populations. In the experiment represented below, different volumes of Letheen Broth were artificially inoculated and plate counts were performed immediately before and after the addition of sponges. The data indicate that both Salmonella and E. coli may be susceptible to die-off in the presence of cellulose sponges but remain healthy and viable with polyurethane sponges.
These factors and others can combine to have adverse effects on microbial populations. In the experiment represented below, different volumes of Letheen Broth were artificially inoculated and plate counts were performed immediately before and after the addition of sponges. The data indicate that both Salmonella and E. coli may be susceptible to die-off in the presence of cellulose sponges but remain healthy and viable with polyurethane sponges.
Improved Recovery from Surfaces
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Aggressive scrubbing during sample collection helps breakup and lift away any biofilms that may be present on the surface, resulting in a more accurate assessment of the microbial populations of the surface.
Polyurethane has a higher tensile strength than cellulose, making it less susceptible to flaking and tearing during sample collection. Therefore, surfaces, including those that are rough and irregular, can be rigorously scrubbed during sample collection without concern that the sponge will deteriorate. Work in our laboratory indicates that polyurethane sponges facilitate comparable or superior recovery of E. coli from artificially inoculated stainless steel surfaces. Similar results were obtained when comparing polyurethane tipped swabs with Dacron tipped swabs. |
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Better Release of Microorganisms
Studies show that cells more readily release from polyurethane sponge material than from cellulose. The inability to release microorganisms after sample collection can have adverse effects on the accuracy of downstream test results causing microbial populations to be underestimated and potentially giving a false sense of cleaning effectiveness.
As demonstrated by the data shown to the left, there was a decreased ability to recover E. coli or Salmonella after cellulose sponges were added to Letheen Broth seeded with either organism. A much higher level of organisms were recovered when polyurethane sponges were added to the inoculated Letheen broth.
As demonstrated by the data shown to the left, there was a decreased ability to recover E. coli or Salmonella after cellulose sponges were added to Letheen Broth seeded with either organism. A much higher level of organisms were recovered when polyurethane sponges were added to the inoculated Letheen broth.
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CELLULOSE AND POLYURETHANE SPONGES FOR SURFACE SAMPLING
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