2.1 Reactive Early Warning Systems

reactive early warning systems

Effective surveillance systems are vital for detecting accidental or intentional contamination in the food chain. At the moment, there are several kinds of surveillance systems operating in developed countries around the world. These systems track and forecast emerging foodborne safety risks through collecting, integrating, analyzing and interpreting data followed by dissemination of the information via reports, advisories and warnings.

Reactive early warning systems can be divided in two types:

  • Endpoint-focused systems: these systems record the occurrence of disease or intoxications as caused by pathogens and toxicants present in the food. These are cases where the actual risk, the end point, has already occurred before filing a report.
  • Hazard-focused systems: these systems measure the presence of the pathogen, toxicant or other hazardous agent in the food or feed. This also includes the occurrence of diseases in livestock that might be transmitted to humans.

2.1.1 Endpoint-focused systems

Disease monitoring systems are in place in many nations. Several systems use a combination of expert opinion with surveillance data (when specially focused on foodborne diseases) or they employ various tools, including Internet.

A couple of examples are given below:

The Dutch Early Warning System (ISIS)

The control of infectious diseases in the Netherlands is carried out by regional public health services, in partnership with regional laboratories. ISIS monitors and describes the day-to-day changes in frequency of all communicable diseases in the Netherlands.  ISIS activities can be divided into notifications of clinical cases and laboratory surveillance. The clinical cases involve practitioners in public health, the public health services, the Inspectorate of Health and the National Institute of Public Health (RIVM), reporting clinical cases and laboratory surveillance. All laboratories connected to ISIS report to a central database every night; clinical and laboratory data are then updated automatically. These are available through Internet. Parts of the site are password protected and can only be accessed by experts. RIVM is in charge of listing, evaluating and informing the government about possible health threats.  

Early Warning Activities in the USA (CDC)

Even though the Center of Disease Control and Prevention (CDC) does not have an early warning system per se, there are several “early warning” activities carried out by the CDC. These include, among others:  

  • FoodNet: The Foodborne Diseases Active Surveillance Network provides a network for responding to new and emerging foodborne diseases of national importance, monitoring the burden of foodborne diseases, and identifying the sources of specific foodborne diseases. FoodNet is a collaborative project among the CDC, nine state health departments, the Food Safety and Inspection Service (FSIS) of the United States Department of Agriculture (USDA), and the Food and Drug Administration (FDA).
  • Foodborne Outbreak Response and Surveillance Unit: Public health scientists investigate outbreaks to control them and to learn how similar outbreaks can be prevented in the future. CDC's Foodborne Outbreak Response and Surveillance Unit provides outbreak reports and publications, an investigation toolkit and reporting forms.  
  • PulseNet is a national network of public health laboratories that performs DNA "fingerprinting" on bacteria that may be foodborne. The network permits rapid comparison of these fingerprint patterns through an electronic database at the CDC. The DNA fingerprinting method is called pulsed-field gel electrophoresis (PFGE).

European Centre for Disease Prevention and Control (ECDC)

The European Centre of Disease Prevention and Control (ECDC) was established in 2005. It is an EU agency which aims to strengthen Europe's defences against infectious diseases.

The ECDC is seated in Stockholm, Sweden and its mission is to identify, assess and communicate current and emerging threats to human health posed by infectious diseases.

In order to achieve this goal, ECDC works in partnership with national health protection bodies across Europe to strengthen and develop continent-wide disease surveillance and early warning systems. By working with experts throughout Europe, ECDC pools Europe’s health knowledge, so as to develop authoritative scientific opinions about the risks posed by current and emerging infectious diseases.

WHO Early Warning Activities

The WHO has a global alert system that methodically gathers official reports and rumours of suspected outbreaks from a wide range of different sources. These reports might include information from ministries of health, national public health institutes, WHO regional and country offices, WHO collaborating centres, civilian and military laboratories, academic institutes and non governmental organisations (NGOs).

Once the raw information has been gathered it is then processed to determine whether or nor the outbreak is of international significance. This is then carried out by the Global Alert and Response Network (GOARN) which is based in the WHO Alert and Response Operation Centre in Geneva, Switzerland.

WHO Surveillance Programme for Control of Foodborne Infections and Intoxications in Europe

In 1980 a surveillance programme for the Control of Foodborne Infections and Intoxications in Europe was established as a WHO and FAO joint initiative. This centre serves as an international focal point for the collection and dissemination of data. Each Member State has a designated contact point – generally the national authority responsible for the surveillance and control of transmittable diseases – to provide information to the collaborative centre on foodborne disease investigation. More information can be found here.

2.1.2 Hazard-focused systems

The examples mentioned below relate to systems that critically collect reports by control authorities of shipments that do not fulfil food safety standards; they also evaluate the implementation of such controls.  Finally they also monitor veterinary diseases, including those that may become a human health issue.

Food and Veterinary Office Early Warning Activities (FVO)

The European Commission is responsible for ensuring that Community legislation on food safety, animal and plant health and animal welfare is properly implemented and enforced. This is the primary role of the FVO. In addition, the FVO must audit/inspect food safety control systems in countries exporting to the EU to ensure compliance with EU standards.

European Rapid Alert System for Food and Feed (RASFF)

The European Food Safety Authority hosts the RASFF as required by the General Food Law. Members, including national food control authorities, are forced to report their measures concerning food safety to RASFF, for instance food and feed recalls and detention of imports that do not fulfil food safety standards. These announcements can be divided into two types:  

  1. The observations or measures that may have implications for other affiliates are nominated “alert notifications”.  
  2. “Information notifications” relate to products that are considered to be without consequences for other affiliates.

Various types of food hazards are commonly reported through RASFF including chemical, microbiological and physical hazards.

Office International des Epizooties (OIE, French for “International Epizootic Office”) World Animal Health Information Systems

The OIE is an international organisation that sets standards for sanitary practices in trade, farming, breeding, therapy and diagnosis of diseases in animals and animal products. These standards serve as reference for the World Trade Organisation in case of international trade disputes over animals or animal products. Members of these organisations have to notify certain veterinary diseases that have been listed by OIE.


SAFE FOODS: Marvin, H.J.P., Kleter, G.A., Prandini, A., Dekkers, S. and Bolton D.J. (to be published), “Early Identification systems for Emerging Foodborne Hazards”, Food and Chemical Toxicology.