6.3 Dishwashing Machines, Trash & Pest Prevention

Mechanical Dishwashing Machine Operations & Maintenance

Commercial dishwashing machines (warewashing machines) automate the washing, rinsing, and sanitizing process. While mechanical dishwashers greatly increase speed and consistency, they must be operated, monitored, and maintained strictly according to manufacturer specifications and FDA Food Code rules to guarantee sanitization.

High-Temperature vs. Chemical-Sanitizing Machines

Mechanical dishwashing machines fall into two main categories based on how they sanitize:

1. High-Temperature Dishwashing Machines:
   • Sanitizing Mechanism: Rely on high-heat water during the final rinse to destroy microorganisms.
   • Temperature Standards: The final sanitizing rinse water temperature at the manifold/nozzle must reach at least 180°F (82°C) for conveyor and multi-tank machines. For single-tank, stationary-rack, single-temperature machines, the final rinse must reach at least 165°F (74°C).
   • Booster Heaters: Because standard facility hot water heaters usually deliver water at 120°F–140°F, high-temp machines require a built-in or external booster heater to raise final rinse water to 180°F.
   • Surface Temperature Verification: Food handlers must verify that item surfaces reach sanitizing temperatures (at least 160°F / 71°C) using irreversible temperature-sensitive indicator strips or a maximum-registering thermometer run through a dish cycle.
2. Chemical-Sanitizing Dishwashing Machines:
   • Sanitizing Mechanism: Utilize chemical sanitizers (such as chlorine or quats) injected automatically into the final rinse water.
   • Temperature Standards: Operate at lower wash water temperatures (typically 120°F / 49°C or per manufacturer EPA label specs).
   • Verification: Chemical concentration must be tested daily using appropriate test strips.

Daily Dishwasher Maintenance & Operation Practices

To ensure dishwashers operate effectively without breaking down, food handlers must follow critical operational guidelines:

• Scrape and Pre-Rinse Items: Scrape food scraps off plates and utensils before loading them into dish racks. Heavy food soils clog spray nozzles and fill scrap trays, lowering washing performance.
• Never Overload Dish Racks: Load dish racks correctly without overcrowding or stacking items on top of one another. Water sprays and sanitizer must reach every surface of every item.
• Check Water Pressure Gauges: Monitor the water pressure gauge for the final rinse cycle. Water pressure must remain within the manufacturer's specified range—typically 15 to 25 pounds per square inch (psi). If pressure is too high, the water atomizes into mist and fails to heat dishes; if pressure is too low, rinse coverage is incomplete.
• Perform Daily Cleaning: At the end of each shift, clear and flush scrap trays and screens, drain the wash tank, and inspect spray arms/nozzles for lime scale or food blockages. Remove mineral deposits (deliming) regularly.

Chemical Safety, Handling & Safety Data Sheets (SDS)

Commercial kitchens utilize powerful cleaning chemicals, degreasers, sanitizers, and lime scale removers. Improper handling or storage of these chemicals creates severe health hazards for employees and risks catastrophic chemical cross-contamination of food.

Safe Chemical Storage Rules

• Separate Storage Location: Store all chemicals, detergents, and sanitizers in a designated chemical storage cabinet or room away from food prep, food storage, utensil storage, and single-service item areas.
• Original Containers: Keep chemicals in their original containers with clear, intact manufacturer labels. If chemicals are transferred into secondary working containers (such as spray bottles), the secondary container must be clearly labeled with the chemical's common name.
• Never Store Chemicals Above Food: Never store cleaning chemicals on shelves above food, prep tables, or clean dishware.

Safety Data Sheets (SDS)

Under OSHA's Hazard Communication Standard (HCS), chemical manufacturers must provide a Safety Data Sheet (SDS) (formerly known as MSDS) for every hazardous chemical supplied to an establishment.

An SDS contains 16 standardized sections detailing:

• Chemical composition and identity.
• Health hazards, symptoms of exposure, and toxicological risks.
• First-aid measures (e.g., eye wash instructions, ingestion protocols).
• Required Personal Protective Equipment (PPE) (gloves, goggles, aprons).
• Safe handling, storage, spill cleanup, and emergency fire response.

Mandatory Rule: SDS binders or electronic SDS portals MUST be accessible to ALL employees at ALL times during every shift. Employees must know where SDS files are located and how to read them in the event of a chemical spill or accidental exposure.

Garbage Handling & Waste Facility Management

Improperly handled garbage attracts pests, creates foul odors, and contaminates food prep environments. Establishments must maintain strict waste management protocols indoors and outdoors.

Indoor Garbage Handling

• Container Construction: Indoor trash cans must be leak-proof, waterproof, pest-proof, durable, and easily cleanable. Containers used for food waste must be lined with plastic trash bags.
• Cover Containers: Keep trash containers covered tightly when not in active use or when full.
• Prompt Removal: Remove garbage from food preparation areas promptly as soon as containers are full. Never allow trash to overflow.
• Clean Containers Frequently: Clean trash cans inside and out frequently in a designated utility sink or wash area—never in food prep or warewashing sinks.

Outdoor Dumpster & Storage Area Standards

• Smooth, Non-Absorbent Surfaces: Outdoor dumpsters, grease barrels, and recycling containers must be placed on a smooth, durable, non-absorbent surface such as poured concrete or asphalt. Never place dumpsters on dirt, gravel, or grass, as spilled liquids soak into the ground and attract rodents.
• Tight-Fitting Lids Closed: Outdoor containers must have tight-fitting lids and doors that remain closed at all times when not actively filling.
• Drain Plugs in Place: Dumpster drain plugs located at the bottom of containers must be kept firmly plugged in place. Plugs should only be removed to drain wash water during cleaning and must be replaced immediately after.

Integrated Pest Management (IPM) & Infestation Signs

Pests such as cockroaches, flies, mice, and rats carry dangerous pathogens including Salmonella, Shigella, and Leptospira. An Integrated Pest Management (IPM) program combines prevention and control to eliminate pests from food operations.

The Three Rules of IPM

1. Deny Pests Access to the Operation:
   • Seal all cracks and crevices in walls, floors, and around pipe penetrations using concrete or silicone caulk.
   • Install weather stripping and door sweeps under exterior doors (ensure no light shows beneath doors).
   • Install 16-mesh per square inch screens on all openable windows and service doors.
   • Install air curtains (air doors) above loading dock doors and rear entrances to blow flies away.
2. Deny Pests Food, Water, and Shelter:
   • Maintain pristine sanitation: clean up spills immediately, sweep food crumbs under equipment, and keep garbage covered.
   • Store all food and supplies at least 6 inches off the floor and away from walls.
   • Eliminate standing water and repair leaking pipes, sinks, and ice machine drains immediately.
   • Rotate food stock using First-In, First-Out (FIFO) to prevent pests from nesting in old boxes.
3. Work with a Licensed Pest Control Operator (PCO):
   • Partner with a certified professional PCO to conduct regular inspections and apply control measures.
   • Never apply restricted-use pesticides yourself. Only licensed PCOs are legally permitted to apply chemical pesticides in food operations.

Identifying Signs of Pest Infestation

Food handlers must recognize early warning signs of pest infestations:

• Cockroach Infestations:
  • Presence of dark, pepper-like droppings in cabinet corners, drawers, or under sinks.
  • Brown, capsule-shaped egg cases (othecae).
  • Strong, oily, or musty odor in enclosed spaces.
  • Live roaches seen during daylight hours (indicates a severe, crowded infestation, as roaches are nocturnal).
• Rodent Infestation (Mice & Rats):
  • Droppings: Black, shiny capsule-shaped droppings (rat droppings are ~3/4 inch long with blunt ends; mouse droppings are ~1/4 inch long with pointed ends).
  • Gnaw Marks: Chewed cardboard boxes, wooden pallets, plastic containers, or electrical wiring.
  • Nests: Shredded paper, insulation, cloth, or packaging material hidden in dark, quiet corners.
  • Grease Rub Marks: Dark, oily smudge tracks along walls and baseboards caused by dirty rodent fur (rodents have poor eyesight and navigate by rubbing against walls).