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EFFECTIVENESS OF CLEANlNG REGIMENS FOR REMOVlNG MILK RESIDUE FROM A PILOT -SCALE HTST PROCESSING LINE
Title
EFFECTIVENESS OF CLEANlNG REGIMENS FOR REMOVlNG MILK RESIDUE FROM A PILOT -SCALE HTST PROCESSING LINE
Creator
Du, Qian
Date
2011-11-30, 2011-12
Description
Undeclared allergens can be introduced into foods due to cross-contact during manufacture. Effective cleaning is essential for preventing...
Show moreUndeclared allergens can be introduced into foods due to cross-contact during manufacture. Effective cleaning is essential for preventing allergen cross-contact on shared processing lines. The objectives of this project were to evaluate the effectiveness of cleaning treatments on removing milk residue from a pilot-scale HTST processing line, and measure the levels of milk transferred into juice processed on an inadequately cleaned processing line. Nonfat milk was processed (81ºC,17 sec) on an HTST processing line followed by several cleaning regimens including 1) a 15 min water flush, 2) a 15 min water flush + a 60 min wash using full-strength chlorinated alkaline detergent (CAD) at 81ºC and a flow rate of 55-60 gal/h , 3) a 15 min water flush + a 60 min wash with ¼-strength CAD at 81ºC and flow rate of 55-60 gal/h, 4) a 15 min water flush + a 15 min full-strength CAD at 81ºC and flow rate of 55-60 gal/h, 5) a 15 min water flush + a 60 min full-strength CAD at 70ºC and flow rate of 55-60 gal/h, 6) a 15 min water flush + a 60 min full-strength CAD at 81ºC and flow rate of 27.7 gal/h, 7) a 15 min water flush + a 60 min full-strength CAD containing 1% milk at 81ºC and flow rate of 55-60 gal/h, 8) a a full cleaning cycle (15 min water flush + 60 min full-strength CAD at 81 ºC + 15 min water flush + 30 min acid detergent at 70 ºC + 15 min water flush + 15 min flush with 200 ppm sodium hypochlorite sanitizer at room temperature, flow rate of 55-60 gal/h). After each cleaning treatment, simulated apple juice was processed on the same processing line, collected and tested for presence of milk using a quantitative ELISA. The adequacy of the cleaning treatments was also assessed by determining the absence/presence of milk residue in sampling ports located in the processing line with ATP swabs, protein swabs and a milk-specific lateral flow kit. All clean treatments and analyses were done in triplicate. Milk was detected at levels of 59-150 μg/mL (ppm) in simulated apple juice processed on the HTST line after a 15 min water flush. No milk was detected in juice processed on the line cleaned with full-strength CAD or a full cleaning cycle. Lower milk levels in apple juice were detected with some of the intermediate cleaning regimens (¼-strength CAD, shorter cleaning time, reduced temperature of CAD, lower flow rate 27.7 gal/h of CAD cleaning and CAD with 1% milk). Swabs of sampling ports revealed the presence of milk/protein residue and high ATP levels after the water flush. Cleaning treatments using full-strength CAD reduced ATP levels and resulted in the no detectable of protein/milk residue in most sampling ports and in simulated apple juice. Reuse of CAD containing high levels of milk may result in milk cross-contact into juice subsequently processed on the milk processing line. This work illustrates the importance of validated cleaning procedures to prevent allergen cross-contact on shared processing lines.
M.S. in Food Safety and Technology, December 2011
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