3M Condensation Management Film (CMFi) Hygienic Evaluation of

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1 Hygienic Evaluation of 3M Condensation Management Film (CMFi)

2 Introduction 3M Condensation Management Film (CMFi)* is designed to evaporate intermittent overhead condensation formed during the warm sanitation process in cooled food processing facilities. The film replaces manual methods for removal of hanging drops of condensate, for example using mops, squeegees, or compressed air. Each of these interventions provide a potential route for lateral and horizontal transfer of bacteria to adjacent or underlying surfaces Two hygienic advantages of 3M Condensation Management Film (CMFi) over these current practices are the elimination of bacterial transfer caused by manual intervention and the ability to periodically remove and replace the film. The recommended interval for removal and replacement of the film is 3 to 6 months, therefore bacterial survivability on the film relative to control surfaces was measured. This document summarizes the results of 3 studies designed to assess bacterial survivability. The first study measured the evaporation rate of hanging droplets of water on CMFi versus control surfaces, demonstrating that water evaporated 8 times faster from CMFi than from a control surface in the study. The second study quantified the survivability of Listeria inocua sprayed onto CMFi and controls adhered to overhead pipes in a 45 F room. After inoculation the pipes were subjected to daily exposure to high humidity to induce condensation on the surfaces. No differences in survivability were observed on the film compared to control surfaces. In the third study, field trials were conducted in which the film was installed on 18 total locations across 5 different cooled food processing plants. Total aerobic microbial counts were obtained using environmental swabs at periodic intervals for each location within the plants. In locations where detectable levels of bacteria were observed there were no significant differences in aerobic counts between CMFi and control surfaces. In total these studies demonstrate 3M Condensation Management Film (CMFi) does not create an environment that affects the proliferation of bacteria differently than control surfaces. * The i in CMFi stands for intermittent. 2

3 Evaporation Studies Drip line. This study was designed to model condensation on pipes, where water droplets accumulate in a drip line by migrating to the lowest point under heavy condensation load. Two-inch wide CMFi was applied lengthwise along the bottom of a 2 inch diameter galvanized steel pipe cooled to 45 F using water circulated through the pipe with a pump. Condensation was induced on the surface using a commercial steam cleaner until steady state dripping was achieved on both surfaces. After removal of the humidity source the time to droplet disappearance was measured. The average time to droplet disappearance of condensate on CMFi was 31 minutes (+/- 5) compared to 298 minutes (+/- 152) for the hanging drops on bare steel (n = 64 total drops). The variability observed in the evaporation rate on control surfaces was caused by the volume difference in hanging drops. Larger droplets took significantly longer to evaporate (maximum = 520 minutes) than smaller droplets (minimum = 45 min). The rapid disappearance of hanging drops on CMFi after the relative humidity drops below the dew point eliminates the need to manually remove condensate, eliminating a potential cross contamination pathway. Images of hanging droplet condensation at time zero (top) and one hour after removal of humidity source (bottom). Data comparing hanging droplet evaporation on CMFi versus pipe. 3

4 Bacterial Survivability Sections of 2 inch wide 3M Condensation Management Film (CMFi) and foil control tape were adhered to 2 inch diameter galvanized steel pipe. Listeria inocua ATCC#33090 was sprayed on to both 3M CMFi and control surfaces. The pipes were then mounted approximately 6 inches below the ceiling in a cooled food processing room and exposed to daily high humidity cycles (96-99% RH) for a time sufficient to induce visible condensation on the pipe surfaces. At each time point three 1 inch wide samples were aseptically removed and placed in sterile 50 ml conical tubes containing neutralizing buffer. The samples were sonicated for 1 minute followed by vortex mixing for 1 minute. Samples were then serially diluted (when needed) in 9 ml tubes of Butterfield s buffer and spread plated on Tryptic Soy Agar (TSA). The plates were incubated at room temperature (~23 C) for 2 hours to allow the recovery of sub-lethally injured cells. After the 2 hour incubation period, an overlay of Oxford Listeria media (OX) was applied and allowed to solidify in a biosafety cabinet. All plates were then incubated for 24 hours at 35 C. Black colonies indicative of esculin hydrolysis by Listeria species on TSA+OX media were counted and converted into Log CFU/in 2. The experiment was repeated 3 times. The average log reduction values are reported in Table 1 below. The average initial inoculum levels were 5.7 +/-0.42 CFU/in 2 on CMFi and 5.2 +/ CFU/in 2 on the control tape. Log reduction values were determined by subtracting the average counts at each time point from the time zero value. Significant differences in survivability between CMFi and controls were not observed. In order to obtain data for later time points it was necessary to perform sample enrichment and record the results as present/absent. Listeria sp. was detected in 5 of 9 samples on CMFi and 9 of 9 on the control surface after 72 hours. Table 1: Survivability of Listeria inocua sprayed on to CMFi and control tape subjected to daily surface condensation. Time (hours) CMFi log reduction Control log reduction Total Plate Count / / / / / / / /- 0.0 Enrichment (Number of positives) 72 5 of 9 9 of 9 4

5 Field Trials Field trials were performed in cooled protein manufacturing facilities at General Mills, Maple Leaf Foods, and Smithfield Foods. Approximately 4 foot long sections of 3M Condensation Management Film (CMFi) were applied to overhead pipes in multiple locations within each plant. Standard daily sanitation cycles were performed at each location with no manual intervention performed on CMFi (mopping, squeegee, or compressed air) for the duration of the trials. Periodic environmental sampling was performed during the duration of each trial to obtain total plate counts for each CMFi location. Results are reported in Table 2 and 3. The majority of locations in plants A-D had no detectable levels of bacteria on CMFi. Comparison to control surfaces was performed in Plant E. No significant differences between CMFi and controls were observed. Table 2: Field trial data Plant Test Locations Within Plant Trial Duration (weeks) Highest Total Aerobic Count on CMFi (all time points) A B C D E 4 7 See Table 3 Table 3: Field trial data at plant location E. Plant E Aerobic Count Location 1 Aerobic Count Location 2 Aerobic Count Location 3 Aerobic Count Location 4 Sampling time (days) CMFi PIPE CMFi PIPE CMFi PIPE CMFi PIPE Conclusion No significant difference in bacterial survivability was observed on 3M Condensation Management Film (CMFi) relative to control surfaces in direct inoculation studies or multiple field trials. Author Information: Evaporation studies were performed at 3M: Steve Swanson, Kurt Halverson, David Peterson. Listeria survivability studies were performed at the University of Nebraska-Lincoln Food Processing Center under the direction of Dr. Jayne Stratton. Plant trials were directed by Karl Thorson (General Mills), Steve Tsuyuki (Maple Leaf Foods), and Dr. Lei Fang and Dr. Kaitlyn Compart (Smithfield Foods).

6 Technical Information The technical information, guidance, and other statements contained in this document or otherwise provided by 3M are based upon records, tests, or experience that 3M believes to be reliable, but the accuracy, completeness, and representative nature of such information is not guaranteed. Such information is intended for people with knowledge and technical skills sufficient to assess and apply their own informed judgment to the information. No license under any 3M or third party intellectual property rights is granted or implied with this information. Product Selection and Use Many factors beyond 3M s control and uniquely within user s knowledge and control can affect the use and performance of a 3M product in a particular application. As a result, customer is solely responsible for evaluating the product and determining whether it is appropriate and suitable for customer s application, including conducting a workplace hazard assessment and reviewing all applicable regulations and standards (e.g., OSHA, ANSI, etc.). Failure to properly evaluate, select, and use a 3M product and appropriate safety products, or to meet all applicable safety regulations, may result in injury, sickness, death, and/or harm to property. Warranty, Limited Remedy and Disclaimer Unless a different warranty is specifically stated on the applicable 3M product packaging or product literature (in which case such warranty governs), 3M warrants that each 3M product meets the applicable 3M product specification at the time 3M ships the product. 3M MAKES NO OTHER WARRANTIES OR CONDITIONS, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OR CONDITION OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR ARISING OUT OF A COURSE OF DEALING, CUSTOM, OR USAGE OF TRADE. If a 3M product does not conform to this warranty, then the sole and exclusive remedy is, at 3M s option, replacement of the 3M product or refund of the purchase price. Limitation of Liability Except for the limited remedy stated above, and except to the extent prohibited by law, 3M will not be liable for any loss or damage arising from or related to the 3M product, whether direct, indirect, special, incidental, or consequential (including, but not limited to, lost profits or business opportunity), regardless of the legal or equitable theory asserted, including, but not limited to, warranty, contract, negligence, or strict liability. Industrial Adhesives and Tapes Division 3M Center, Building 225-3S-06 St. Paul, MN (Fax) 3M is a trademark of 3M Company. 3M 2017