Devon Zagory, Ph.D.
Senior Vice President for Food Safety & Quality Programs Food Safety & Quality Programs, Davis Fresh Technologies, LLC
From: The Packer, November 29, 1999. "Prevention is the only policy for producers."
Why all the excitement about food safety all of a sudden? Is foodborne illness from produce new? Is it worse than it used to be? What are we supposed to do about it? These and other questions about food safety are often asked when produce professionals gather. And answers tend to be in short supply. However, there sometimes seems to be plenty of blame to go around. It is the fault of the newspapers, of television, the government, consumers, big agriculture, genetic engineering, and so on. The truth is both less sinister and more difficult than many believe.
Food borne illness associated with produce is not new but our awareness of it may be. People have been getting sick from eating food for a long time but we, perhaps, didn't realize it until recently. When, in the past, we have said that we had the "stomach flu," we really had foodborne illness. The flu is a viral disease that causes fever, headache and achy muscles. Vomiting and diarrhea are not common symptoms of the flu but they are common symptoms of food borne illness. While food- borne illness from eating produce was and is a rare event, it does happen, sometimes with dire consequences.
While we may prefer to believe that produce is not a vector for human pathogens, science and public health agencies have become much more sophisticated in tracking down the causes of food-borne illness and they are increasingly looking at fruits and vegetables as likely suspects. So if we admit that produce has, at times, been the culprit, and that it is likely to be again in the future, then we must ask ourselves what we can reasonably do to reduce the likelihood that our products are to blame.
Many believe that they have programs that prevent their products from carrying pathogens and making anyone sick. Chlorinated water, ozone, ultraviolet light, "antibacterial" packaging materials, irradiation, organic acid washes and microbiological testing all have their place in produce sanitation. But the simple fact is, once fruits and vegetables have been contaminated with bacterial pathogens or parasites, none of these methods will assure the safety of the product. It is possible to reduce the numbers of pathogens on produce by washing in sanitized water, but it is not possible to eliminate them through any of the above means. And if a few bacterial cells remain on the surface, it only takes a few hours at warm temperatures for those few cells to become many cells. The only treatment we currently have available that will completely eliminate pathogens from fruits and vegetables is thorough cooking. And most people prefer their salads raw.
If we can't remove pathogens from produce, what can be done? The answer is simple: prevention. Prevent fruits and vegetables from getting contaminated in the first place. In produce food safety, prevention isn't the best policy, it's the only policy! This is the reason for the current focus on GAP's (Good Agricultural Practices), GMP's (Good Manufacturing Practices) and HACCP (Hazard Analysis Critical Control Point) programs. They are all preventative programs to keep pathogens off fresh produce. The difficulty comes because pathogens can get on produce from many different paths and at any time during growing, harvesting, packing, processing, distributing or handling. So preventative programs cannot start and stop at your doors. There must be a continuous chain of prevention throughout all of the steps involved in getting fruits and vegetables to Americas tables.
Before we can prevent pathogens from getting onto our products we have to understand how they get there. Most of the pathogens of potential concern on fresh produce come from one of four sources: Contaminated water, animals and their manure, infected workers or soil. If we are aware of these sources, and manage them in all phases of our operations, we can effectively prevent produce from becoming contaminated. Good sanitation practices should focus on those places and practices where contamination of food is most likely. Contamination of fruits and vegetables with pathogens is most likely to occur from:
Prevention programs start with identifying specific places in an operation where risks of contamination from the above sources could occur. For each identified risk there should be a program that addresses and minimizes that risk. For example, if animals are grazing upslope from a vegetable production area, berms and ditches can be constructed to divert runoff away from the growing vegetables. In this way the risk has been identified and minimized.
As another example, if workers contact product with their hands in a harvest operation, packing shed or processing facility, there is a risk of contamination of the product from infected workers. Several steps may be taken to address these kinds of risks. A company policy should be articulated, in writing and through worker training, that workers who are ill may not handle product. The training materials should make it clear to the workers why this policy is so important. Where possible, temporarily divert recently sick workers to jobs that do not involve contact with product. Establish and enforce policies regarding hand washing after using the toilet, before working with product and after touching anything that may be a source of cross contamination, such as garbage or plant material on the floor. Such policies should be enforced through oversight by supervisors and worker training sessions and those sessions should be documented. The importance of hand washing and instruction in proper hand washing should be a central part of worker training. Ensure that bathrooms are clean, well stocked and accessible. If bathrooms are unpleasant to enter or use, workers are less likely to use them.
As can be seen from the above examples, in some cases there may be no single, simple remedy for an identified risk. It may be that many small things must be done to address a risk. This is why risk reduction can be difficult and require substantial commitment, attention, resources and multiple programs. In many cases no single program, neither HACCP nor GMP's nor GAP's, will fully and effectively address all risks. Risk assessment and mitigation requires systematic analysis, careful planning, creative solutions and commitment at all levels of the company. But the time has come when ignoring the risks of foodborne illness, or making believe that they are not serious, has passed. The responsibility to provide ever safer, more wholesome food rests with each of us and the reward will be the continuing trust of our customers that we are providing them with the best, safest products possible.