2. Lesson 2.1 Avenues for Contamination
Templates for:
Case Notes 2.1 l Assignment 2.1

3. Case Notes 2.1

4. Case Notes 2.1 (cont.)

5. Case Notes 2.1 (cont.)

6. Case Notes 2.1 (cont.)

7. Career Assignment

8. Career Assignment (cont.)

9. From Farm to Table: Lettuce

10. Iceburg lettuce field and harvest unit
Head lettuce harvest unit
Iceburg lettuce field and harvest unit
Hand harvest and coring

11. Field packing into bins
Field conveyor
Field packing into bins
Head lettuce on conveyor in field.

12. Worker utilizing field hand washing station

13. From Farm to Table: Milk

14. Milking parlor Cows feeding
Cows feeding These are cows eating feed in the a tie stall operation.  Feeds are often a mixture of specific rations (e.g., grains, silages) designed to give the cow optimum nutrition for milk production and heath.  Poor quality feeds or poor ventilation in dairy barns can lead to feed off-flavors in the milk.
Milking parlor Very large milking parlor.
Milking parlor
Cows feeding

15. Small High Temperature Short Time (HTST) pasteurizer
Small HTST pasteurizer Small High-Temperature Short-Time plate heat exchanger for milk pasteurization.  Milk flows counter to steam/hot water (milk on one side of a thin stainless steel plate, hot water on the other side = equals indirect heating) in the heating section to heat the milk to a minimum of 161 F (72 C) to be held for a minimum of 15 seconds for legal pasteurization (most milk is treated above minimum).  The heat section is on the left which connects to the "holding tube" to meet the time requirement.  The middle section, call the "regeneration section" is where energy is saved by heating cold raw milk with hot pasteurized milk (after the legal hold time) in a counter flow.  This section has raw milk on one side the plate heating up as it moves forward by hot pasteurized milk on the other side of the plate which is cooled down by the raw.  If there is a leak, the plate cross-contamination is a concern.  The section on the right is the cooling section where milk must be cooled to < 45 F or 7 C.  Pasteurized milk from the regeneration section flows counter to chilled water or glycol on the other side of the plates.  Milk form the pasteurizer then goes to a holding tank.
Small High Temperature Short Time (HTST) pasteurizer

16. Images courtesy of Liz Van Buren
Batch tanks
Temperature recorder
Extended Shelf Life (ESL) Batch Tanks Used to store specific batches prior to heat.  Similar tanks may be used for other storage needs.  Shows pumps, valve clusters, etc.
VAT temperature recorder A vat or "batch" pasteurizer where milk is heated in a vat to 145F or 63C for 30 minutes minimum (also legal pasteurization).
Images courtesy of Liz Van Buren

17. Extended Shelf Life (ESL) Steam injection Aseptic storage tank
Extended Shelf Life (ESL) Steam injection This is a steam injection, high heat (280F or 138C for 2 seconds minimum) system used for Extended-Shelf Life Milk (ESL).  Milk is rapidly heated by directly injecting steam into the milk.  The water vapor must be removed which is done so by vacuum (the big cone shaped item).
Aseptic Storage Tank
This picture shows pasteurized milk storage tanks (silo) recessed in the wall in an Extended-Shelf Life Plant associated piping and valve cluster.  After milk is heat treated (either pasteurized or in this case Ultra-Pasteurized) it is generally stored bulk in Pasteurized Milk tanks before it goes to a package filling machine.  These tanks and all associated equipment are sanitized, or for ESL, sterilized (thus the heavy duty doors in the picture), before milk is processed.  The valve cluster (left hand corner) allows the operator to direct the milk from several tanks to several filling machines.  All piping and tanks in a dairy operation is stainless steal and other materials (e.g., rubber parts, gaskets are food grade, 3-A approved).
Images courtesy of Liz Van Buren

18. Images courtesy of Liz Van Buren
Extended Shelf Life (ESL)-EH1 Filler Package filling machine that forms, fills and seals paper-board cartons.  Milk cartons are purchased as folded four sided tubes with the top and bottom open.  The filler first seals the bottom by heat (a polymer layer on the carton), then fills the carton with milk, then seals the top.  This is an ESL machine designed for days shelf-life with filtered air, H2O2 treatment for the carton before filling treatment and sterilization procedures for the machine itself.  For conventional pasteurized milk (14-18 days shelf-life) fillers may or may not have filtered air, are sanitized (not sterilized) and have no carton treatment.
Extended Shelf Life (ESL)-EH1 loader Bottled milk is automatically loaded into cartons or boxes prior to being sent to the cooler and shipped.  This picture shows cartons with "fitments" or the screw-cap which are punched into the carton prior to filling.
Filler
Loader
Images courtesy of Liz Van Buren

19. Milk light case Milk light case
Milk in a typical display case, exposed to fluorescent lights which can cause off-flavors and vitamin reduction (as can sunlight but the effects are much quicker).
Milk light case

20. National GAPs Program © 2007 Department of Food Science
Department of Education
Cornell University
Ithaca, NY 14853