Reinforcing the Links in the Food Safety Chain 36889

 Reinforcing the Links
in the Food Safety Chain
July 1996 -- Food Safety

By: Scott Hegenbart
Editor*

*April 1991-July 1996

  When the safety of food is compromised, the effects -- in addition to the potential loss of human life -- can be staggering. In 1992 alone, the medical costs and productivity losses due to foodborne pathogens were estimated to be somewhere between $5 billion and $6 billion ("Food Safety Issues: Modernizing Meat Inspection," Agricultural Outlook, 197, 1993).  In 1989, the Council for Agricultural Science and Technology (CAST), Ames, IA, created a task force to determine the state of knowledge about U.S. foodborne disease risks. The task force's findings were released in a 1994 report entitled, "Foodborne Pathogens: Risks and Consequences."  Among the report findings are that the "Application of hazard analysis critical control point (HACCP) systems can reduce the likelihood of foodborne illness." The report further states that "pathogens and their toxins can enter the food chain at any point from the farm to the kitchen."  By designing hurdles along the entire length of this chain, the reduction of incidence and prevention of contamination, etc. would contribute to the overall safety.  This series of articles has been developed to demonstrate how food safety is affected at various points along the entire food production chain and to offer examples of how it is/might be controlled. Although proper testing and monitoring certainly would be an important part of such a comprehensive HACCP plan, the emphasis has been given to identifying ways to reduce the incidence of potential hazards.  Once a food product is manufactured, it must be protected from contamination while being distributed to retailers and, ultimately, consumers. Although it may serve a variety of protective and marketing roles, a product's package is also a link in the food safety chain because it provides a physical barrier to recontamination. As obvious as this may seem, "Foodborne Pathogens: Risks and Consequences," a report on the state of food safety in the United States issued in September 1994 by the Council for Agricultural Science and Technology, Ames, IA, is strangely silent on the subject of packaging.  In fact, other concerns frequently supersede packaging's primary role as a food protector. For example, the concern for being "green" in Europe has caused many European food companies to use less packaging material and, consequently, products aren't lasting as long. This hasn't caused any safety problems yet, but it would be doubly unfortunate if it did. First, compromising food safety can be dangerous and, second, industry sources have theorized that the savings of solid waste from packaging materials may very well be negated by the increased solid waste from spoiled products anyway.  "We always have this tension about packaging and the environment versus safety," says Julie Miller Jones, professor of foods and nutrition at the College of St. Catherine, St. Paul, MN. "I'm too firmly entrenched in the safety camp to give up product life and safety."The proper package  For the package to maintain food integrity, it first must be properly designed. Naturally, this means the packaging material should sufficiently resist penetration by microorganisms or disease-carrying insects. The material also must be capable of being sealed properly.  Some food applications are even sensitive to the introduction of microorganisms from the packaging material itself. The most obvious example of this is aseptic processing in which the package and product are sterilized separately. Currently, aseptic packages are sterilized with a chemical agent. Researchers, however, are examining the use of pulsed-light treatment as a non-chemical alternative. In this process, an ultra-high-intensity flash of light inactivates harmful microorganisms on the surface of the packaging material.Making packages smarter  In addition to the barrier itself, other packaging-related techniques can help reduce food safety concerns. Modified-atmosphere packaging (MAP) is one such method. Here, a specific gas atmosphere placed inside the package can be used to slow bacterial growth on the food. MAP must be applied carefully, however, because excluding air isn't always a good idea. Clostridium botulinum is an example of anaerobic bacteria. These thrive in oxygen-free atmospheres, and removing oxygen and/or replacing it with another gas may actually create an ideal environment for Clostridium growth.  Boxed beef is one bacteria-sensitive product that is vacuum-packed and back-flushed with carbon dioxide. When meat packed this way is kept under strict temperature control and is properly handled, bacterial problems are not an issue. Certain cuts, however, are available to consumers in this form of packaging, so there is a potential hazard from consumer temperature abuse.  Sous vide foods are another example where anaerobic bacteria may be problematic. This sort of product is popular with consumers since it appears minimally processed because it is vacuum-packed and given only a mild heat treatment.  "This is sufficient enough to kill most bacteria, but not the spores of Clostridium botulinum," says Michael Doyle, Ph.D., professor and department head, department of food science and technology, center for food safety and quality enhancement, University of Georgia, Griffin. "The consumer may then abuse the product. It may smell good and taste good, but it might house a large colony."  Other safety barriers -- such as an acid or preservative -- could be added to the sous vide product, but this would go against the organoleptic advantages of the process.  Another potential way to make packages smarter that's under investigation is to add antimicrobial agents directly in the packaging material.  "Nobody is doing it commercially; it's a research issue," says Steve Taylor, head of the department of food science and technology, University of Nebraska, Lincoln (UNL). "But if you recognize that many microorganisms will be only on the surface of a product, if you treat the surface effectively, you may not have to worry about the rest of the product."  UNL researchers are developing antimicrobial-containing edible films made of food-grade proteins or carbohydrates. These films could be used on beef to control surface microorganisms. As an extra advantage, the film improves shelf life. A more practical example comes in the form of the mold inhibitors currently incorporated into cheese packaging. Even though cheese mold doesn't produce mycotoxins, this example serves as a model for controlling microorganisms through packaging additives.  Remember, however, that surface microorganisms aren't the only food safety problem. "With Clostridium botulinum, the organism may be within the tissue," says Doyle. "The same is true if you're dealing with a comminuted product where the outside gets mixed in."  Fish, as another example, may be sold whole and the Clostridium botulinum spores may be found in the intestinal tract.  Package design is half of the food safety link. The other half is assuring the integrity of the package when the product leaves the production line. Traditionally, this has been achieved through the visual inspection of seals from random samples off the line. New computer scanning systems offer the potential to examine virtually every package to determine if there is a leak or if there are minor faults in the material or seal. These systems aren't ready for broad commercial use yet, but their development is proceeding rapidly.  Making sure that everything is sealed is one way to ensure safety," says Jones. "These machines perform the kinds of things that we used to rely on humans to do -- an extremely boring task that requires an almost impossible level of alertness."Packages on the move  Once a package is sealed, the manner in which the product is distributed will affect its safety until it reaches the supermarket. The factor that most obviously affects safety during distribution is the temperature at which temperature-sensitive products are transported.  When working with a new product that is temperature sensitive, a food designer will want to study the distribution chain and determine points along the way where temperature abuse may occur. These points then should be confirmed and tested.  Small electronic temperature monitors are readily available for this sort of testing. They can be placed in crates along with product packages, or they can even be packaged inside a carefully marked package. After traveling through the distribution network, the monitors are retrieved and their memory is downloaded to a personal computer for analysis.  Most such devices come equipped with software designed to display the encountered temperatures as a function of time. By correlating this with the trucking logs, product designers can determine where and when temperature abuse occurs and, subsequently, devise improvements to the distribution network. With the cooperation of, say, a supermarket chain, the distribution network could be studied almost to the point where a consumer selects the product from the refrigerator case or freezer.  After making such an effort to optimize distribution temperatures, a way to monitor distribution on an ongoing basis also is necessary. Indicator labels offer one way to perform such monitoring. These labels are designed to change color if a product is exposed to temperatures outside of a specified range for a certain amount of time. In addition to monitoring for temperature abuse, the labels serve as a visual reminder to workers along the distribution chain to be more attentive to potentially abusive treatment. According to the suppliers of such labels, many manufacturers report that products receive better handling during distribution when the labels are in place. These suppliers also state that consumers quickly learn to use the labels to select fresh product and to monitor freshness when the product is stored in their own refrigerators.  To some industry sources, involving consumers in any sort of food safety monitoring seems like nothing short of a miracle. When this series concludes with the next article, readers will learn that while packaging and distribution are important, they aren't nearly as challenging to food safety as the final links in the chain: consumers and other food handlers.Back to top<