In recent years, food safety has been threatened by a number of events and developments that allow food borne microorganisms pathogenic to humans, e.g., the bacteria Salmonella, Listeria, Escherichia coli strain, the protozoa Cyclospora, Cryptosporidium, and Giardia, and the hepatiti, A virus, to reach and contaminate our food in a variety of ways.
- Increased processing of fresh plant produce (e.g., fruit juices, fruit or vegetable purees, cole slaw, fruit sections and cut-up vegetables for salads in bulk or in plastic bags) that may sometimes contain produce that carries a significant amount of food-spoiling bacteria and mycotoxin-producing fungi.
- Inadequate food processing procedures that allow survival of human pathogens in the processed product
- Long storage of foods that encourages the development of pathogenic microorganisms.
- Application to fruit and vegetable fields of improperly aged or poorly treated manure that carries human pathogens.
- Application on the plants of irrigation water that may be carrying one or many of the aforementioned human pathogens due to contamination by humans and animals through run-off of waste waters, etc.
- Unacceptable hygiene of harvesters, handlers, and packers after using the toilet that results in the contamination of fruits and vegetables with human pathogens.
- The presence of pets, livestock, and wildlife animals, some of which may carry human pathogens on
their bodies or in their feces to fruits and vegetables.
- To these should be added the ever-increasing shipment of food items among various geographical points of a country and worldwide, which may greatly multiply and expand the effects of a local contamination of food products.
One of the main effects of fears about food safety is economic. Not only is it costly to take all measures necessary to secure food safety, but there is also the fear and cost of rejection of produce shipments at the point of destination. Similarly, there is the possibility of refusal of buyers to purchase produce from farms that do not meet the buyer’s food safety standards.
In the United States and other developed countries, many of the large buyers of food products for their mills, processing factories, or chain stores demand third party audits of farms by certified specially trained individuals and consulting firms regarding the employment by the farm of all necessary precautions in the type of manure they may be using, the quality of water used for irrigation, the health and hygiene of their workers and plant handlers, and so on.
Also, to avoid unjustified accusations of offering contaminated produce, farmers are or will soon be expected to have a traceback system in place. This will happen by identifying all produce leaving the farm as to origin and date of packing so that if contamination is found in the produce in the marketplace, the source will be easy to identify and appropriate measures may be taken. Also, it will become necessary to keep food safety records, such as documenting worker training sessions, recording the results of water tests, details of manure applications, if any, of dates, methods, and rates of irrigation, and so on, as well as of disease outbreaks among the farm workers. To protect themselves from purchasing contaminated produce, buyers of large quantities will test or have the produce tested with serological and molecular-based diagnostic technique that can already detect, for example, as few as three Salmonella cells per 25 grams of naturally contaminated food.
In addition to the aforementioned types of contamination of food with pathogens, there are the additional threats of contamination with pathogenic microorganisms that are resistant to antibiotics, such as streptomycin and tetracyclines used in plants, as well as in humans and animals; the presence in the food of genetically engineered plants that contain genes for chemicals toxic to insects, such as the Bacillus thuringiensis toxin; genes for antibiotics against other human pathogens; genes for activating defensive mechanisms of plants, often through the production of proteins and phenolic compounds that make the plants resistant to insects, diseases, and to herbicides; genes for edible or otherwise delivered human vaccines and antibodies (planti bodies) against human pathogens; genes for unrelated proteins that may be allergenic in some individuals; and even genes for producing plastic.
There is fear in some segments of the population, especially in developed countries, that although some of these genes are introduced into inedible plants such as tobacco, plants with such genes will intentionally or accidentally find their way into foods and feed and will affect adversely the health of animals and humans. Many large produce distributors or retailing companies and manufacturers of food products simply refuse to buy any produce that comes from genetically modified organisms (GMOs), plants, or animals.
Molecular based diagnostic tests have also been developed that detect introduced genes that may not have been declared as being present. Since the horrendous terrorist attack in New York and Washington, DC, in September of 2001 and the subsequently declared war against terrorists wherever they exist, there is an added fear of having food contaminated intentionally by terrorists. Contamination could be carried out with human pathogenic microorganisms, such as those mentioned earlier or with others, e.g., the bacterium causing the disease anthrax, or with toxic substances.
Contamination of produce can be done while the latter is still in the field, in transit, or in grocery stores. There is also fear of having the drinking water or the water used for irrigation of fruits and vegetables contaminated intentionally by terrorists with pathogenic microorganisms or with toxic substances that will then find their way to humans via the food distribution system.