Biofilm Removal from Stainless Steel Surfaces Using Abrasive Mechanical Disruption Combined with Low-volume Electrostatic Application of Sanitizer Spray

Summary

As the first step in development of a process that would combine mechanical disruption and spray technology, this study evaluated using abrasive mechanical disruption (particulate abrasion) and air-assisted electrostatic-induction spray sanitizer application, in tandem, to remove biofilms from stainless steel surfaces.

Situation

Bacterial biofilms on stainless steel food processing equipment compromise food safety and quality. Using a combination of two proven sanitation methods, abrasive mechanical disruption and charged electrostatic spraying of sanitizers, may yield an effective low-volume sanitation process to remove biofilms.

Response

A mechanical abrasion chamber was fabricated so the abrasive particulate stream was directed at stainless steel coupons containing Listeria monocytogenes biofilms. Each coupon was subjected to an airborne stream of abrasive particulates (425-710 µm; 5.83 g/min) impacted upon coupon surfaces for 10 at average power densities of 59.4 and 16.1 mW/cm2. Then levulinic acid and sodium dodecyl sulfate (SDS) sanitizer was applied so equal quantities of active ingredient were dispensed using either an air-assisted, induction-charged electrostatic nozzle with droplet charging ON (~ -7 mC/kg charge-to-mass) or with charging OFF or with a conventional hydraulic nozzle. For accurate spray application, nozzles were attached to a repeatable robotic arm. The methods were evaluated for the reduction in quantity of L. monocytogenes on the stainless steel surfaces.

Impact

Abrasive mechanical disruption combined with air-assisted electrostatic charged spray of organic acid sanitizer [6% levulinic acid and 0.6% SDS or 0.44 full-rate peracetic acid (PAA)] effectively reduced the number of biofilm cells by > 99.999%. Bacterial biofilms present significant obstacles in food processing environments. Development of a process that can deliver abrasive mechanical disruption and low-volume electrostatic application of sanitizer spray may provide an effective means for biofilm control.

State Issue

Food Safety

Details

• Year: 2012
• Geographic Scope: National
• County: Clarke
• Program Areas:
  • Agriculture & Natural Resources