Chemical Dosing for Food Safety & Sanitation

Sodium hypochlorite is governed by pH. The active biocide is hypochlorous acid (HOCl), which dominates between pH 6.5 and 7.5. Above pH 8, the equilibrium shifts to the hypochlorite ion (OCl⁻), which is ten to eighty times less effective against vegetative pathogens. FDA Food Code 4-501.114 codifies this with explicit temperature minimums per pH range.

Typical engineering targets:

• Food contact: 50–200 ppm free chlorine
• pH window: 6.5–7.5 (HOCl dominance)
• Min solution temp: 75°F at 50 ppm, pH ≤ 8
• Produce wash control: 650–750 mV ORP

Quats are cationic actives, which is why pre-rinse is non-negotiable: residual anionic detergent neutralizes the quat before it reaches the target organism. The Food Code requires a 200 ppm minimum and a contact time of at least 30 seconds at 75°F.

Typical engineering targets:

• Food contact: 200–400 ppm
• Min contact time: 30 seconds
• Min solution temp: 75°F
• Hardness limit: 500 mg/L unless label permits otherwise

PAA is the workhorse of modern wet sanitation because it works broadly and rinses cleanly. It exists in equilibrium with hydrogen peroxide and acetic acid, decomposes faster at elevated temperatures and high pH, and breaks down into water, oxygen, and acetic acid at label rates — which is why it satisfies no-rinse use on food contact surfaces under the 21 CFR 178.1010 framework. PAA has displaced chlorine in many high-care RTE environments precisely because it is effective against Listeria monocytogenes, Salmonella, E. coli O157:H7, and norovirus surrogates.

Typical engineering targets:

• Food contact: 80–200 ppm
• Produce wash: 60–80 ppm with pH control
• No-rinse under 21 CFR 178.1010

CIP operates on different physics. Chlorinated alkaline detergents saponify fats and hydrolyze proteins through a combination of chemistry, heat, and mechanical shear. None of these chemistries tolerate a 30 percent dilution error.

Typical engineering targets:

• Caustic: 1–2% at 140–180°F
• Acid rinse (phosphoric/nitric): 0.5–2%
• CIP velocity: ≥ 5 ft/s (turbulent flow)

The table below maps the most common food safety chemistries to the Dosatron injector model and dilution range typically specified for the application. Use it as a starting point for SSOP design — a Dosatron application engineer will confirm final model selection based on flow rate, inlet pressure, concentrate viscosity at operating temperature, and chemical compatibility.