Evaluating Current Industry Dry Cleaning Practice Using Vacuum with Regard to Food Allergens on Processing Surfaces

Introduction: Allergenic cross-contamination is a growing concern for the food industry, which has been reflected in increasing number of incidences of undeclared allergen contamination according to USDA.  Especially, the cleaning methods used in low moisture environments where water cannot be used is an area of concern.  Therefore, evaluating current industry practices is necessary to determine if new methods are required or current methods are satisfactory.

Purpose: The purpose of this study was to determine the effectiveness of the vacuum dry cleaning method used in the food industry.

Methods: Stainless steel coupons were electrostatically coated with soy protein isolate powder as an allergenic material.  The coupons were then subjected to vacuum cleaning at about 3 mm above the surface.  After 10 seconds of vacuuming followed by a brushing, second vacuuming was applied for 10 seconds.  Then, the coupons were tested for the presence of the soy allergen using Neogen 3D Reveal test kits.  For cleaning efficacy, another set of coupons was vacuum treated, after which the coupons were submerged and agitated in 15 mL of deionized water in a plastic bag.  The total dissolved solids (TDS) and conductivity were measured for the wash water using a water quality meter.       

Results: The allergen tests showed 50% negative and 50% positive for soy (n=6), which indicates the uncertainty of the vacuum cleaning practice for allergen removal.  The mean TDS, 4.72 ± 1.57 ppm and the conductivity, 3.7 ± 0.5 micro S/cm, supports the mixed allergen test results.  The results of the vacuum cleaning test provided further evidence that visual cleanness poses the risk of allergen cross-contamination.

Significance: Although the current industry vacuum cleaning practice is considered as an effective and practical dry cleaning method, it needs to be further validated and improved to ensure allergen safe food products.