Air cooling and heating coils used in food processing equipment from Colmac Coil Manufacturing, Colville, Wash., is said to offer anti-microbial properties where there is concern about possible food contamination with pathogens.

Recent research has shown that exposure to the surfaces of certain metal alloys will kill cultured colonies of E.coli and L. monocytogenes within just a few hours at temperatures as low as 39°F (3.8°C). Based on this research, according to the company, Colmac Coil’s fin construction design exhibits aggressive anti-microbial behavior - equivalent corrosion resistance to stainless steel and similar heat transfer performance to standard coil construction.

According to Colmac, the coil construction provides benefits such as:
  • Killing bacteria where UV lighting cannot reach.
  • Corrosion resistance to harsh cleaning chemicals.
  • Anti-microbial protection of the entire heat transfer surface.
  • Elimination of a need for coatings that can chip and flake off.
“Conventional fin and tube coils with many rows deep are inherently difficult to clean and sanitize,” says Bruce Nelson, president of Colmac. “The active anti-microbial behavior of this new fin material kills bacteria even deep in the interior spaces where UV lighting and other disinfection methods just cannot reach.”

When combined with stainless steel tubes, the coil construction resists corrosion when exposed to normal concentrations of cleaning chemicals commonly used in the food processing industry such as potassium hydroxide (caustic soda) and sodium hypochlorite (chlorine bleach). The company will incorporate the anti-microbial coil construction into a line of cooling equipment such as process room evaporators, critical process air handler coils, proofing coolers, cooking oven coils, and individually quick frozen (IQF) and spiral freezer coils. The coils are compatible with commonly used refrigerants such as ammonia, CO2, halocarbons, glycols and brines.