HHS:PHS:FDA:CFSAN:OFP:DCP:MST 
 
      200 C Street, SW 
      Washington DC 20204
 
      M-I-01-5
 
      December 31, 2001
 
 
TO:  		All Regional Food and Drug Directors 
      Attn:  Regional Milk Specialists
 
FROM:  	Milk Safety Team (HFS-626)
 
SUBJECT:  	Concerns with Tetra Pak's Vacuum Thermal Instant Sterilizer (VTIS)
Higher Heat Shorter Time (HHST) Pasteurizer and Aseptic Processing System Vacuum
Chambers
 
 
Problems regarding the construction and cleaning of this equipment have been
observed in the field. This memorandum explains the concerns, provides Tetra
Pak's response to these concerns and suggests possible regulatory follow-up
actions.
 
 
Background
 
The vacuum chambers in question are a part of Tetra Pak's VTIS HHST and aseptic
steam injection milk and milk product processing systems. The purpose of the
vacuum chamber is to remove the water, added during steam injection, and to
provide the initial cooling of product leaving the holding tube. 
 
These systems have been in use for over twelve (12) years in the United States.
Currently these systems are in operation in approximately twenty-two (22)
milk-processing plants across the U.S. 
 
During the past year, FDA Regional Milk Specialists have observed serious
construction and cleaning problems associated with these vacuum chambers.
 
While investigating these problems, the Milk Safety Team (MST) has learned that
an older design, sold from 1989 to sometime in 1998, is likely to have
construction problems. These construction problems generally include internal
welds that are not completely joined in the product contact area. These problem
welds are in the product inlet and distribution passages, located along the
inner wall of the chamber. The welds in the product inlet passage and in the
first part of the product distribution passage can only be seen by using a scope
inserted into the product inlet passage. When it is possible to remove the outer
cover or bell, the welds in the last section of the product distribution passage
can also be evaluated using a scope inserted into the outlet of this passage.
While the welds in post 1998 vacuum chambers are more likely to be satisfactory
for the intended use, all of these chambers should be examined.
 
Cleaning of this equipment has also raised concern. Minor deviations from the
manufacturer's cleaning recommendations can result in thick layers of product
build up on product contact surfaces. Serious cleaning problems in the product
inlet and distribution passages have been observed in both the pre- and post
1998 designs.
 
 
Tetra Pak's Response
 
Tetra Pak has begun using a scope to view and videotape the condition and
cleanliness of the product inlet and distribution passages of every VTIS vacuum
chamber installed in a milk plant in the U. S. They plan to have all of them
examined and video taped by May 2002. State regulators and FDA Regional Milk
Specialists have been and will be notified when they will perform these
examinations. 
 
All equipment found needing repairs will be repaired and re-examined. 
 
The cleaning regimens of all equipment found soiled will be re-evaluated and
modified as needed. The equipment will be re-examined at approximately weekly
intervals until it is found clean or is removed from service. 
 
Examination of these chambers will continue on a periodic basis for as long as
this equipment remains in use. The examination frequency for clean equipment
that does not need repair, or has been adequately repaired, will be
approximately each six (6) months to start.  If the Regulatory Agency agrees,
this frequency may be extended as long as the equipment is found clean at each
examination. If it is found soiled, the cleaning regimen will be re-evaluated
and modified as needed. The equipment will be re-examined at approximately
weekly intervals until it is found clean or is removed from service. 
 
 
Suggested Regulatory Follow-up
 
MST suggests that State regulators and, when possible, FDA Regional Milk
Specialists, accompany the Tetra Pak technicians when they examine and video
tape the vacuum chambers. MST has noted that despite efforts to "stiffen" the
scope, it can fall from the viewing position where the upper portions of the
distribution passages can be observed. It is these upper areas that are most
likely to be soiled. Simply viewing the video, after the fact, can be confusing.
If the scope falls to the bottom, it can in some cases, look a lot like the top.
The outer cover or bell should be removed, if possible, and the distribution
passages examined from the outlet end of this passage. 
 
While MST recognizes that Regulatory Agencies have the right to deal with these
concerns in whatever manner they choose, we suggest that if the vacuum chamber
is examined, repaired and monitored as described above and is consistently clean
when periodically examined, that this existing equipment continues to meet the
requirements of the Grade "A" PMO.  
 
MST has been informed that Tetra Pak, Inc. is redesigning the vacuum chamber to
make all surfaces visible for inspection and make it easier to clean. 
 
We suggest that all new installations be of the new design when it becomes
available. 
 
Copies of this memorandum are enclosed for distribution to Regional Milk
Specialists, State Milk Regulatory Agencies and State Milk Sanitation Rating
Officers in your region. This memorandum will also be available on the FDA Web
site at http://www.cfsan.fda.gov at a later date and should be widely
distributed to representatives of the dairy industry and other interested
parties. 
 
 
 
 
 
      Robert F. Hennes, RS, MPH
      Chief, Milk Safety Team
 
 
 
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M-I-01-5	1	 December 31, 2001