In This Section |
Troubleshooting Films and Deposits on
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| Author: | Paul Norris - Milk Quality Assurance Program Lead/OMAFRA |
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| Creation Date: | 01 May 2000 |
| Last Reviewed: | 01 May 2000 |
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| Fat/Grease | • hanging water droplets with greasy
(white) appearance • oil |
• improper pre-rinse (cold water) temperatures • low final temperature during cleaning cycle • improper detergent concentration • regular use of acids during washing cycle • pulsator oil on equipment surface |
• initial cleanup with a chlorinated alkaline detergent with hot water — double up on label usage rate | • regular and proper cleaning procedures • coupled with acidified rinse • use warm (100°F-120°F or 38°C-49°C) pre-rinse water • proper cleaning with proper use dilution during each cleaning cycle • don't let waste water drop below 120°F or 49°C |
| Protein | • blue-rainbow hue, varnish like apple sauce | • using non-chlorinated cleaner • inadequate pre-rinse • improper (sporadic or periodic) cleaning • too hot pre-rinse |
• initial cleanup with equal parts of chlorine and a chlorinated alkaline detergent with hot water — double up on label usage rate | • use a chlorinated alkaline detergent • clean with appropriate dilution during each cleaning cycle • adequate pre-rinse with warm (100°-110°F or 38°-43°C) water • rinse before milk film dries on equipment surfaces |
| Milkstone or Waterstone | • white to yellow | • mineral from milk • mineral from water • no acidified rinse |
• initial cleanup with a chlorinated
alkaline detergent with hot water — double-up on label usage rate • acid wash |
• regular and proper cleaning procedures
coupled with acidifier rinse • periodic acid wash in addition to the normal cleaning cycle |
| Mineral, Calcium, Magnesium | • white (water-stone), chalky to gray | • improper rinsing • dropout of minerals from water supply • no acidified rinse |
• acid wash with hot water (double up on label rate) | • use acid rinse regularly • make sure that alkaline product used has good water-conditioning properties • use water softener |
| Iron | • brown to red | • water supply • aggressive supply system components • no acidified rinse |
• acid wash with hot water | • regular effective acid rinse • water treatment • proper selection of sanitizers |
| Inking (Blacking) | • black rubber parts | • reaction between chlorine or chlorinated compound and rubber | • acid wash with hot water — if not removed, replace | • acid rinse • proper dry storage |
| Black | • black residue deposit | • rubber migration • contact of dissimilar materials |
• acid wash with hot water — if not removed, replace | • acid rinse • proper dry storage |
| Factory Soil | • grease, factory dirt-black deposit, rusting | • improper or no initial cleanup | • initial cleanup with equal parts of chlorine and a chlorinated alkaline detergent with hot water — double up on label rate | • thorough cleaning before equipment is used initially |
| Corrosion | • rust, pitting | • iron, tramp metal particles, improper chemical usage | • acid wash and abrasive action • repolishing (buffing) if advanced corrosion |
• proper cleaning procedures and passivating acid (makes the stainless steel surface less reactive) |
| Etching | • pitted and white discolouration “imbedded” in stainless steel surface | • improper use of chemicals • improper use of chemicals |
• repolish | • proper cleaning procedures and passivating acid rinse (makes the stainless steel surface less reactive) |
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Plastics: |
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| Opaque | “Foggy”, white not clear | Improper draining, moisture absorption | Exposure to heat and/or sunlight | • blower or dryer • good drainage |
| Yellow | Yellow colour | Old age, improper use of iodophors, hand soil stain | None | Proper product application |
| Brown, Black | Brown discolouration | Rubber migration, carbon from dryer motors | Acid wash — if not removed, replace | • use acid rinse regularly • proper filtration • segregation of plastics and rubber |
| Red | Red colour, stain | Serratia marcescens | None | Use proper cleaning procedures regularly |
| Pink, Purple | Pink to purple colour | Streptococcus rubriticuli | Strong alkaline wash | Use proper cleaning procedures regularly |
* Films and deposits are caused in part by poor procedures (improper cleaning, rinsing, etc.) and by incompatible products. In mechanical cleaning, problems may also be due to malfunction of the system or lack of proper solution control.
Source: The Professional's Approach to Quality Milk Production. Dr. David Reid and Dr. Andy Johnson, 1993
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