Foodborne pathogens

Hippocrates in 460 BC reported that there are as strong connection between food consumed and human illness.

What is a pathogen? A pathogen is defined as an organism causing disease to its host, with the severity of the disease symptoms referred to as virulence. Pathogens are taxonomically widely diverse and comprise viruses and bacteria as well as unicellular and multicellular eukaryotes.

A pathogen brings disease to its host. Another name for a pathogen is an infectious agent, as they cause infections. As with any organism, pathogens prioritize survival and reproduction.

Foodborne pathogens are biological agents that can cause a foodborne illness event. Foodborne pathogens are a concern for both public health officials and the food and dairy industries.

There are five main types of pathogens: Bacteria, Viruses, Fungi, Protists, Parasitic worms

Common foodborne pathogens including:
*Campylobacter
*Clostridium botulinum
*E. coli O157:H7
*Listeria monocytogenes
*Norovirus
*Salmonella
*Staphylococcus aureus
*Shigella
*Toxoplasma gondii
*Vibrio vulnificus

Campylobacter sp. (mostly associated with raw or undercooked poultry) is the major foodborne pathogen in the U.S. food supply, causing more than two million infections per year, while Salmonella, mostly found in meat, poultry, and eggs, is responsible for more than one million cases of food poisoning.

Foodborne illness occurs when a pathogen is ingested with food and establishes itself (and usually multiplies) in the human host, or when a toxigenic pathogen establishes itself in a food product and produces a toxin, which is then ingested by the human host.

In recent times, a significant number of people have died due to foodborne diseases, and such pathogens are a priority and a critical health issue all over the world. It was reported that roughly one of every six Americans in the U.S.A. get sick, the number of hospitalized patients is 128,000, and 3000 people die due to foodborne diseases annually.

The factors contributing to the emergence of foodborne diseases are changes in human demographics and behavior, technology and industry, and international travel and commerce; microbial adaptation; economic development and land use; and the breakdown of public health measures.
Foodborne pathogens

Foodborne disease outbreak surveillance system

Surveillance is a systematic collection, analysis and interpretation of data essential to the planning, implementation and evaluation of public health practice and the timely dissemination of this information for public health action.

At the government level, surveillance is essential for rapid detection of a foodborne disease outbreak. CDC created the Foodborne Disease Outbreak Surveillance Systems in 1973 to collect data about cases of foodborne disease that are contracted by two or more patients as a result of ingesting a common food.

Ideally surveillance systems detect small clusters of illness rapidly. There are two types of surveillance, active and passive.

In passive surveillance, in order for a disease outbreak to get noticed by the CDC or health department, a chain of events must occur:
*Exposure of the general public
*Person becomes ill
*Person seeks medical attention
*Specimen is obtained
*Laboratory test for the organism
*Laboratory confirms the case
*Report to Health Department/CDC
The data help focus public health actions intended to reduce illnesses and deaths caused by foodborne disease outbreaks.

Traditional foodborne disease outbreak surveillance systems utilize passive surveillance systems to detect suspicious clusters of foodborne illnesses or outbreaks. Yet only 8% of symptomatic persons seek medical care and only a small proportion of these seeking care diagnostic testing to determine an etiology for their illness.
Foodborne disease outbreak surveillance system

Changing lifestyles increased risks of foodborne disease

In the recent years the reported incidence of foodborne diseases has continued to increase worldwide, with a number of extremely serious outbreaks occurring on virtually every continent.

Changing lifestyles have resulted in a number of changes to people eating habits.
*More people now eat out, which had led to an increased demand for catering establishments of varying type. Going to restaurants frequently, eating foreign cuisine and consuming fresh fruits and vegetables increase the risk of foodborne disease.

*Many more women work outside the home and rely on processed foods for fast meal preparation; this has meant that knowledge of how to handle and prepare foods has decreased in recent years.

*Increased mass production of foods has increased the potential for larger numbers of consumers to be affected in the event of an outbreak of foodborne disease.

*People demand a wider variety of food than in the past and nowadays almost every type of fruit is available on the international food markets the entire year round regardless of seasonal changes in growth.

*Increased tourism has meant that people are exposed to foodborne hazards form other areas.
Food disease change due to changing lifestyles

*Consumption patterns may enhance unhealthy food production and distribution because desires ubiquitous availability of all foods at low prices.
In this day of ever changing lifestyles and very increasing demands on the consumers’ time and energies, consumers are demanding convenience, freshness, long shelf lives and little preparation time before consumption.

The increasing incidence of foodborne diseases is due to a number of factors, including changes on food production on the farm, new system of food processing, longer distribution chains and new food preparation and storage method.

Food technology has responded by applying knowledge of science to produce an increasing array of new foods, some partially processed, minimally preserved of high quality and with extended shelf life.
Changing lifestyles increased risks of foodborne disease

Microbial Grouping

Microbial Grouping
The microbial groups important in foods consist of several species and types of bacteria, yeasts, molds and viruses. Bacteria, yeasts, molds and viruses are important in food for their ability to cause foodborne diseases and food spoilage to produce food and food ingredients.

Many bacterial species and some molds and viruses, but not yeasts are able to cause foodborne disease.

Most bacteria, molds and yeasts, because of their ability to grow in foods (viruses cannot grow in foods, can potentially cause food spoilage.

Several species of bacteria, molds and yeasts are considered safe of food grade or both and are used to produce fermented foods and food ingredients.

Among the four major groups, bacteria constitute the largest group. Because of their ubiquitous presence and rapid growth rate even under condition where yeast and molds cannot grow, they are considered the most important in food spoilage and foodborne disease.

Prion or proteinaceous infectious a particles have been identified to cause transmissible spongiform encephalopathies (TSEs) in humans and animals.
Microbial Grouping

Epidemiology and Foodborne Illnesses

Epidemiology and Foodborne Illnesses
Most of what is known about foodborne illness started with epidemiology, the study of disease in a population. John Snow, a London physician, used deductive reasoning, research and interviews in the 1880s to determine the cause of a cholera epidemic that had killed more than 500 people in one week.

Scientists used Snow’s technique to investigate primarily infectious diseases until the 1920s, when the field broadened to include clusters of all factors that apply to the incidence of disease among people.

Epidemiological techniques have improved over the years, In 1970s, Dr. Paul Blake developed the case control method.

This method compares those who became ill with closely matched individuals who stayed well.

By examining what those who became ill did differently from those who stayed well, the source of infection can often be revealed.

In the case of foodborne illness an ill person is question about where and what they ate and matched as closely as possible in age, health status and eating pattern to someone who stayed well in an effort to pinpoint differences.

In the Centers for Diseases Control and Prevention (CDC) works to help treat and prevent disease at the national level and has increased its scope to lent epidemiological assistance worldwide because of the overlap between the developed and less developed worlds.

The people who pick and pack fruits and vegetables in foreign countries that are imported the United States are handling the US food supply.

If foreign worker have illness that can be transmitted through food, their illness have a direct bearing on our health.

Foodborne illness is most often linked to bacteria, but there are other agents that can cause foodborne illness, including viruses, parasites, prions and molds.

Bacterial illness is the most prevalent but viruses and parasites are being spread through food more commonly than in the past.

Each types of disease agent has different characteristics that must be considered when implementing food safety strategies.
Epidemiology and Foodborne Illnesses

Control measures

Control measures
The ubiquity of potentially life-threatening pathogens in our environment, the ability of some of them to survive or proliferate under refrigeration and in reduced oxygen atmospheres, and for some of them, the low number necessary for disease production indicate the seriousness of the potential hazards with which we are faced.

The food industry utilizes a variety of effective control measures to limit potential hazards. This is accomplished by destruction or inactivation of the relevant bacteria or their spore through the use of heat treatments, dehydration, freezing, refrigeration, specialized packaging approved anti-microbial preservatives.

Additionally, extensive quality control procedures are maintained to ensure that these processes are effective. It is for these reasons that American food supply remains the safest most wholesome in the world. However, recent consumer trends toward lower dietary salt (and thus low salt or salt free foods), towards the elimination of preservatives, and towards minimal processing significantly affect control measures and product shelf life and greatly limit the variety and type of food available.

While the food industry employs necessary control measures to ensure the safety of food until it reaches the consumer, all food handlers and consumers have the responsibility upon purchase of the food to maintain these control measures until consumption.

Any compromise of control measures, such as time or temperature abuse, alteration of product integrity, may result in growth and toxin production of pathogenic microorganisms.
Control measures

Foodborne disease

Foodborne disease
The pattern of Foodborne disease has changed substantially in industrialized countries in recent decades. Outbreaks are more likely to be far reaching, and some are even global in scale because of widespread food distribution and changes in methods of food preparation. Further changes in the incidence of foodborne disease and the pattern of food-related illness can be anticipated from global warming. As a result of changed conditions in food production and better laboratory detection techniques, new foodborne pathogens continue to be identified. In particular, we are now faced with the emergence of antimicrobial drug–resistant bacteria and a number of viruses not previously recognized.

Foodborne disease is a public health concern in all parts of the world. In the United States, foodborne disease causes an estimated 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths each year. In the United Kingdom, an estimated 2.37 million cases of foodborne gastroenteritis occurred in 1995. Previous estimates of foodborne gastroenteritis in Australia have ranged from 1–2 million to 4 million episodes per year. The effect of such large numbers of persons with gastrointestinal illness is considerable.

A recent national survey of gastroenteritis in Australia found that one third of working adults miss ≥1 days of work when they have gastroenteritis, and another third of cases result in a caregiver missing work. In Australia in 2003, 99 reported outbreaks of foodborne disease affected 1,686 people and caused 6 deaths. Any evidence of food contamination can also have a major effect on food industry and trade. The food industry in Australia generates >$29 billion in food production, with >20% of products exported, and $57 billion in food processing.
Foodborne disease