Reinforcing the Links in the Food Safety Chain 31960

Reinforcing the Links
in the Food Safety Chain
May 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.

  When developing a new formula, product designers serve as an important link in the food safety chain. Foods may be subjected to a number of treatments that act as protective barriers to either kill or control pathogens. These traditionally have included pasteurization, sterilization, acidification, preservation, water activity reduction, low-temperature storage (refrigeration or freezing), and modified-atmosphere storage.

  "Because a single barrier often is insufficient to ensure food safety, a combination of several barriers may be used," according to the report, "Foodborne Pathogens: Risks and Consequences," issued by the Council for Agricultural Science and Technology (CAST), Ames, IA.

  The combination of barriers devised by the formulator forms the safety web that helps protect the food's integrity and quality. Often, designing this web requires delicate balancing; if one barrier is minimized, the others must be optimized to compensate. For example, a product concept might call for minimal processing. In such a case, the product's pH might be lowered or its water activity reduced to control microorganisms. On the other hand, the reduced water activity and increased acidity may affect the product's organoleptic quality, and refrigerated distribution and storage may prove necessary to ensure quality and safety of the minimally processed food.

  In all cases, the success of the safety web must be confirmed by shelf life testing of control products and those spiked with known microbial loads.

Ingredient initiative

  Devising and optimizing the safety web may be a relatively simple task, or it may seem to require nothing short of a food science miracle. Before designers can get to the task of optimizing the components of the web, however, attention must first be given to the ingredients included in it.

  "HACCP starts right at the beginning with ingredient control," 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. "You want to be sure the ingredient doesn't have specific organisms."

  When specifying ingredients for a product that is sensitive to bacteria, for example, look for those that have low counts, if the ingredients are known to contain bacteria. In addition, have in-house testing performed to confirm the results of the specification sheet. Some ingredients may vary widely from the reported averages.

  Remember, too, that a single ingredient's bacterial load may not be the most crucial issue. The ingredient may potentiate the growth of organisms that occur naturally in other formula components. For example, researchers have found that chocolate milk supports larger populations of microorganisms than white milk.

  If such preliminary examinations look promising, some companies may choose to select a designated supplier. This relationship can be advantageous for both parties, but it should not take the place of periodic testing for monitoring purposes. In 1994, a major cereal manufacturer discovered that 21 million bushels of oats had been tainted with an unauthorized pesticide. Earlier monitoring tests could have prevented the financial and public relations losses the company endured when approximately 50 million boxes of cereal had to be recalled and destroyed. This is not to say that suppliers can't be trusted, but companies must take steps to guard against errors and the darker side of human nature.

  "You can have a supplier that has been with you for years and years and suddenly needed some extra money," says Julie Miller Jones, professor of foods and nutrition at the College of St. Catherine, St. Paul, MN. "So, unfortunately, you can't totally rely on the supplier."

  In the quest for quality ingredients, the issue of cost inevitably will arise. Beware of deals that seem to good to be true. One apple juice processor thought it had found a terrific source of inexpensive apple juice concentrate, but it turned out to be adulterated with sugar and water. The problem was eventually caught by an observant quality control staffer who noticed that the incoming apple juice was too consistent for a natural product.

  "Unfortunately, you usually get what you pay for," says Jones. "If there is a great disparity in price, be really skeptical and search out how their vanilla, apple juice, or whatever, can cost so much less than that from another supplier."

Process groundwork

  With suitable ingredients selected, the product designer must perform preliminary tests to confirm that the product's processing parameters assure safety.

  With retorting, the importance of this homework was a lesson learned early. According to Reay Tannahill in her book, "Food in History" (1989 Crown Publishers Inc., New York), canning was a relatively new technology in the mid-1850s, producing primarily 2- to 6-lb. cans. Hoping for steady government business, several English companies attempted the same process on 9- to 14-lb. cans to supply the Admiralty. At that time, the expulsion of air, rather than the destruction of microorganisms by heat, was believed to preserve the food. Consequently, the heat was not adequate to kill the bacteria in the center of the larger cans. One naval supplier condemned 111,108 lbs. of meat in these large-sized cans as unfit for human consumption.

  Now that we know the true functional mechanism behind canning, such incidents are easily avoided. Right? Not necessarily. Within the last decade or so, a mushroom canner decided to expand its market beyond small, in-home consumers by canning #10 cans of mushrooms for foodservice pizza. The increase in can size was not compensated for adequately in processing, resulting in a minor food poisoning outbreak.

  Again, the subject of balance must be emphasized because over-processing the mushrooms would make them mushy and unsuitable for use as a pizza topping. The company may have needed to optimize the heat treatment and seek some ingredient intervention to be successful.

Altered safety states

  In recent years, product designers have had to face new challenges for formulating safe foods in the form of altered products, such as reduced-salt, reduced-fat, and convenience foods. According to the CAST report, the introduction of new food products with reduced levels of microbial inhibitors such as sodium chloride and the proliferation of ready-to-eat refrigerated convenience foods with an extended shelf life are among the factors that contribute to the increased concern about foodborne pathogens. For example, reducing salt and nitrate on bacon must be done carefully because both control Clostridium botulinum. The same is true for the salt in pasteurized processed cheese spread.

  "In both cases, the salt reduction can be done, but you have to be vigilant," says Steve Taylor, head of the department of food science and technology, University of Nebraska, Lincoln. "When you remove salt, you must remember that it has antimicrobial properties."

  Reducing fat often involves increasing the level of water. This could make the product more susceptible to microbial growth. Even if the added water doesn't create a safety concern, it may make the product spoil faster. For example, researchers have found that low-fat ground beef with fat substitutes -- and, thus, more water -- will spoil faster at refrigerated temperatures. Reduced-fat ground beef without an added substitute will not behave significantly different from regular ground beef.

  Convenience foods invariably require some form of shelf life extension whether they are shelf stable or require refrigerated storage. Food safety must always be a primary concern any time shelf life is extended.

  "If we extend shelf life, we're often increasing the possibility of a safety problem," says Doyle. "Something processed and eaten in a short period of time is less likely to be abused and allow Clostridium botulinum to grow."

  Listeria monocytogenes serves as another example. Extending the shelf life of a product may not increase the rate at which this microorganism grows, but it does extend the time that it can grow to large populations that are harmful.

  Many of the challenges of altered products go back to the safety web analogy. Reducing one part of it requires adjusting the others to compensate.

  Product designers indeed are a critical link in the food safety chain. Without them, the remaining safety barriers may not ever be put into place.

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