How the Danish control Salmonella in eggs
Salmonella in Danish table eggs is as close to zero as possible, the result of long-term partnerships and frequent testing.
Denmark has one of the lowest levels of Salmonella in table eggs in Europe. All European Union member states must apply Salmonella control programs, but Denmark has implemented a testing regime that is stricter than European requirements, and the country’s egg producers and consumers have seen the benefits.
Starting at the beginning
Salmonella controls in Denmark date back to at least the 1980s, yet they were not always successful. Between 1980 and 1997, a fivefold increase in human infections occurred, according to figures released by the Ministry of Food, Agriculture and Fisheries, with only 5-10 percent of infections thought to have been registered.
This rise in human cases of salmonellosis prompted to the government to act and introduce a program under which reduction targets were set for contaminated flocks, followed by rolling reduction targets.
Denmark operates a top-down surveillance and elimination strategy, under which infected flocks are eradicated by means of compulsory destruction or stamped out from the table egg industry with any potentially infected eggs having to be pasteurized.
Since the launch of the program, the prevalence of infected flocks has been reduced from the more than 20 percent to less than 0.5 percent. Keeping this level low is achieved through regular sampling along with a variety of preventive measures.
Flock Salmonella sampling
Denmark’s Salmonella flock sampling program comprises serological and bacteriological analyses and all serotypes are tested for.
- All layer parent stock is tested every week
- All breeding flocks are tested four times during the breeding period, using a variety of analyses
- All table egg flocks are tested bacteriologically every second week with two pairs of sock tests
Where parent flocks or layers are concerned, should positive results be returned for Salmonella eteritidis, S. typhimurium, S. hadar, S. virchow or S. infantis, the flock is removed from production.
Should tests detect other strains of Salmonella, retesting must be carried out.
Denmark’s authorities and egg producers exert a high degree of control over production.
While sampling will detect any rise in infection levels should they occur, numerous prevention measures are also in operation to help ensure that this does not happen, although neither vaccination nor antibiotics are used.
The country operates import restrictions on day-old chicks, and farms must be cleaned and disinfected before the arrival of new flocks.
Should a farm be found to be persistently infected or re-infected, heat/steam disinfection is carried out, and a task force may be sent in to help with farm management.
All poultry feed must be heat treated to a minimum of 81C.
HACCP and various codes of practice are in place in all production sectors that are connected to eggs.
The initial Salmonella control plans were drawn up by the Danish government and egg industry in conjunction with other stakeholders.
At first, government funding was made available for the culling of infected flocks, as the government sought to quickly bring the number of infected flocks to less than 5 percent. However, since 2002, all costs of the program have been covered by industry.
Mie Nielsen Blom, chief adviser for food safety and veterinary issues with the Danish Agriculture and Food Council, notes that the benefits of the program have been various.
Human salmonellosis attributable to Danish eggs is now considered very low, meaning that possible illness or deaths have been prevented. Additionally, the country has secured a European Union guarantee allowing it to reject imports of eggs that are not guaranteed to be Salmonella free. The country’s high Salmonella status has put the Danish egg industry in an excellent position where egg exports are concerned.
Similar programs are in operation in Denmark for the control of Salmonella in the broiler and swine industries.
The number of Salmonella-infected layer farms in Denmark has steadily declined, and infection levels in eggs are as close to zero as possible.