Food-Grade Liquids

Liquids ·

Food-grade liquids encompass the full range of consumable fluids processed in the food and beverage industry — from thin, watery products such as fruit juice and beer through to highly viscous materials such as honey, chocolate and ketchup. They represent approximately 5% of all pump applications globally, but impose uniquely strict requirements around hygiene, cleanability, materials of construction and the mechanical gentleness of the pumping action.

Regulatory and Hygiene Standards

  • EHEDG (European Hygienic Engineering and Design Group): European standard for hygienic equipment design — defines surface finish requirements (Ra ≤ 0.8 µm), drain-ability, absence of dead legs and clean-in-place (CIP) compatibility
  • 3-A Sanitary Standards (USA): American standard equivalent to EHEDG — specifies materials, surface finishes and design details for dairy and food equipment
  • FDA 21 CFR: US regulations for materials in contact with food — approved elastomers, plastics and coatings
  • EU Regulation 1935/2004: Framework regulation for food-contact materials in Europe
  • ATEX: Applicable where alcoholic beverages, solvents or flammable cleaning agents are used in the hygienic production area

Liquid Categories and Properties

  • Thin aqueous products: Milk, whey, fruit juice, beer, wine, spirits — viscosity 1–10 cSt; standard centrifugal or positive-displacement at low shear
  • Viscous products: Tomato paste, fruit concentrates, vegetable purees — viscosity 100–10,000 cSt; non-Newtonian; gentle pumping required
  • Highly viscous and sticky products: Honey, glucose syrup, caramel, jam — viscosity 1,000–100,000 cSt; steam-jacketed pump and piping needed
  • Shear-sensitive products: Cream, mayonnaise, live culture yoghurt, fruit pieces in juice — mechanical damage by high shear or turbulence destroys product structure
  • Aerated products: Whipped cream, ice cream mix — contain deliberately incorporated air; centrifugal pumps destroy the foam structure

Surface Finish Requirements

  • Internal wetted surfaces: Ra ≤ 0.8 µm (mechanical polish) for EHEDG; Ra ≤ 0.6 µm for dairy duty; Ra ≤ 0.4 µm for pharmaceutical-grade products
  • External surfaces: Ra ≤ 1.6 µm to prevent crevice colonisation by microorganisms
  • Welds: Internal welds must be fully penetrated and continuously dressed to the same finish as surrounding surfaces — no crevices or pitting
  • Drain-ability: All internal surfaces must drain completely by gravity — no pooling that could harbour bacteria between batches

Pump Type Selection

  • Thin, non-shear-sensitive liquids: Hygienic centrifugal pump — impeller and casing polished to EHEDG standard; mechanical seal in food-grade elastomer
  • Shear-sensitive or viscous products: Lobe pump or circumferential piston pump — low-shear positive displacement; gentle handling of intact cells, fruit pieces and structured emulsions
  • Highly viscous syrups and honey: Progressive cavity or gear pump with steam heating — temperature-controlled to maintain pumpable viscosity
  • Aerated or fragile foam products: Peristaltic pump — tube isolates product; no shear; maintains foam structure
  • Dosing of flavours, preservatives, acids: Membrane metering pump — precise, contamination-free

Clean-in-Place (CIP) Requirements

  • Pump must withstand hot caustic (2% NaOH at 70 °C) and hot acid (1% HNO₃ at 70 °C) CIP cycles
  • All seals and elastomers must be chemically compatible with CIP chemicals and steam sterilisation (SIP) at 140 °C
  • Pump must be fully drainable and free of dead volumes to allow complete flushing
  • PTFE, EPDM and silicone are the most commonly approved elastomers for food-grade and CIP service

Applications

  • Dairy — milk reception, pasteuriser feed, cream separation, yoghurt and cheese production
  • Beverage — beer transfer, wine pumping, juice concentration, soft drink blending
  • Confectionery — chocolate tempering and transfer, caramel and toffee dosing
  • Sauces and condiments — ketchup, mayonnaise and dressing batching and filling
  • Bakery — dough and batter handling, filling injection
  • Edible oils — olive oil, sunflower oil and palm oil refining and transfer
  • Brewery and distillery — wort transfer, yeast handling, spirit transfer