Virginia Polytechnic Institute and State University

Susan Duncan, Dairy and Sensory Evaluation

Bill Eigel,                Food Biochemistry

Joe Marcy:               Food Processing

Merle Pierson: Food Microbiology

 Sean O’Keefe: Food Chemistry

Susan Sumner:   Food Safety

Walter Hartman:    Dairy Plant Manager whartman@vt.edu

Kim Waterman:  Dairy Chemistry    Kwater@vt.edu

Brian Yaun: Microbiology byaun@vt.edu           Phone: (540) 231-8697

  Research Highlights

Efficacy of Ultraviolet Light Treatment for the Reduction of Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Species in Raw Fluid Milk

Kristen Matak is a Ph.D. candidate in the Department of Food Science and Technology.

 Dairy products made from raw milk are a traditional food practice common in many cultures.  In the past decade, there have been a number of illnesses associated with these types of products.  Preference for raw dairy products is linked with perceived superior organoleptic characteristics that cannot be obtained when the milk is heat-treated.  It is supposed that the consumption of raw milk products will continue regardless of education programs or increased governmental regulations.  The U.S. Code of Federal Regulations and the Grade “A” Pasteurized Milk Ordinance address the possibility for alternatives to heat treatment.  Less expensive alternatives to pasteurization have been developed in response to FDA’s new fruit juice regulations.  Studies using the CiderSure 3500 UV apparatus have confirmed that UV (ultraviolet) processing will achieve a 5-log reduction of Cryptosporidium parvuum and E. coli in apple cider.  The UV apparatus was designed with computer monitored UV sensors placed within the apparatus to adjust the flow rate according to sensor readings to ensure that all of the cider receives the same amount of UV light.  The opacity issues of apple cider and fluid milk are similar and it is believed that the bactericidal benefits of this apparatus would be successful with any semi-opaque fluid.  The objective of this research is to measure the dose-response to UV irradiation for the reduction of pathogens in raw milk.  Chemical, nutritional, and sensory changes will also be assessed. 

HOT TOPICS AND DAIRY ISSUES

 Biosecurity in the Dairy Plant

The dairy industry has long dealt with issues of food pathogens and inadvertent adulteration.  In the wake of 9/11 and with the current war with Iraq, the need to ensure the safety and security of dairy products has intensified, and operations should be reviewed from a new perspective.  This article describes areas to consider from milk and other materials entering the plant to final product distribution.

The first line of defense for any dairy plant is employees.  Educate them on the importance of vigilance and ask them to watch for unusual events or suspicious behavior.  Consider performing background checks into immigration status and criminal history of potential employees and be sure to check references.  Train all new employees in security and documentation procedures (including temporary workers) and enforce these policies.  Account for all keys to the facility and change combinations or collect retired key cards when employees are terminated.  Employee lockers should be secured with company owned locks and company procedure should permit access to these areas for periodic inspection.  Employee clothing can be color coded so that it is easy to spot if people are in a restricted area.  Uniforms should not have pockets that could allow employees to bring personal items into food handling areas.  It is important to restrict casual or temporary employees to designated areas and to put a good Production Manager in charge of these workers. 

Develop a sign-in procedure and have an escort available for visitors and vendors.  If a vendor rep is unfamiliar, call the vendor to verify their identity.  Visitors should present a photo I.D.  Security cameras positioned at strategic points around the plant and monitored at a central location provide excellent protection against intruders.  An electronic security system requiring a magnetic card for entry is also a good idea. 

Suppliers should have biosecurity measures in place. They should be able to provide information on driver identification, driver background checks and measures taken to assure that potential food safety issues are recognized and controlled.  Review these procedures and work with the supplier if there are concerns about potential risks.  

Voluntary guidelines have been suggested by IDFA for sealing raw milk tankers.  Trucks should never be left unlocked and unattended, whether full or empty.  Nobody should have access to the inside of the tanker while the truck is parked unless they are unloading or cleaning it.  Access points to tankers should be tagged or locked for tamper-resistance or tamper-evidence at each step of the journey, and records of these seals should be maintained. Plants should take steps to establish protocols to follow for determining acceptability of receiving milk from the tanker if seals are broken.  This protocol should be communicated to owner(s) of all milk received and to plant management. The same security should be applied to trucks that distribute final products. Records of product distribution, consignee and product code (lot number) also need to be maintained. The receiving location should verify seals and seal records before unloading.   

Supervise off-loading of all incoming materials and compare materials with actual receipts.  Missing or extra stock or other irregularities outside the normal range need to be investigated.  The receiving bay should have restricted entry and the door leading into the plant should be equipped with a security device such as a keypad.  Sample points, pumps and other equipment in this area need to be secured.

Inlets outside the plant for liquid bulk ingredients need to be secure and checked on a daily basis.  Opened bags of dry ingredients should be stored in a secure place and need to have the name of the operator who last used them and the date they were last used written on them.  Destroy outdated or discarded product labels to prevent product counterfeiting. Ammonia, gas cylinders and other chemicals need to be stored in a secure area.  City water supplies need to be investigated to find out what security measures are in place, and private wells need to be locked and secured.

Plant and warehouse perimeters (outside entrance and egress) and air intake points should be equipped with appropriate fencing, gates, guards, sensors, video surveillance and outside lighting.   Inside the plant, restrict access to chemical storage, lock/secure all access that might permit entrance to the plant or material storage outside the plant (silos, etc.).  Keep within the fire code!  Protect access to computer production records.  In the processing area, maintain the safety and security of the equipment through cleaning records and control of employee traffic and access.  Be sure that procedures and documentation for processing rework are in place and followed.