Summer and fall present the greatest challenges in preventing mold spore contamination at North American food processing facilities. Annual mold complaints typically spike during the warmer and more humid months of the year when conditions are ideal for microbial growth. With reported spoilage rates approaching 5% seasonally in some facilities, mold contamination may create a quality problem resulting in excessive product rejection, reduced shelf life, and negative feedback from consumers. Elimination of mold spores in a food production facility is not practical and would be a monumental achievement. Instead product contamination mitigation utilizing a system of measures working in tandem is required to achieve best results.While critical sanitation alone cannot prevent atmospheric molds from landing on product. Ninety-five percent of the time goods may be susceptible to contamination is during the cooling and conveying process after leaving the ovens or fryers where any mold spores present may land on product. A primary measure is enclosing cooling conveyors and where possible providing a filtered air supply to capture most of the spores.
Most mold spores are at least 1-micron or larger in size existing primarily in the 3 to 10 micron range. If your objective is to reduce mold spores by ninety percent, a filter should be selected based on a particle size of 3-10 micron at 90% efficiency. Synthetic materials should be selected as a preventive measure against potential mold growth in areas with moist air streams and high relative humidity which may create food safety concern.
The best enclosure and filtration systems are of little value if the space is operated in a negative pressure drawing molds or other airborne contaminants into the enclosure. Enclosed conveyors such as spiral coolers should be slightly pressurized with
either filtered outside or conditioned plant air with gentle relief through conveyor openings acting as an indirect source of plant make up air. One of the key developmental requirements of our proprietary Spiral Product Conditioning System in 1999 was to help bakeries address mold exposure.
Caution should be heeded to not automatically select the highest level of filtration. Filtration efficiency should be based on tolerance levels of each ventilated space as there are several associated costs. Filter media price, energy consumption changes, and potential degraded system performance must be considered in a cost to benefit ratio prior to selection for existing equipment. Additionally always consult a qualified air filtration specialist or mechanical contractor familiar with your equipment and ASHRAE guidelines prior to altering MERV ratings.
Please contact us if interested in learning more about reducing mold spore exposure in your production space.