Food safety
The safety of meat depends on the way the animals are grown and on the handling at the slaughterhouse - read about pathogenic bacteria and residues.

A high level of food safety is one of the preconditions for Danish pig production. The pig meat is characterised by a very low incidence of pathogenic bacteria, drug residues and other unwanted compounds.

The food safety depends on both the primary production - the way the pigs are grown - and the handling of the meat during and after slaughter.

Zoonoses and pathogenic bacteria
Zoonoses are diseases that can be transferred from animals to humans. It is diseases caused by bacteria, vira or parasites from domestic animals. Most zoonoses from pig meat are caused by bacteria, e.g. Salmonella and Yersinia.

Salmonella
Human beings are most frequently contaminated with Salmonella through foods of animal origin (meat eggs etc.). The disease occurs 6-72 hours after the ingestion of the bacteria, and the symptoms are diarrhoea, stomach pains, fever, headache and sometimes also vomiting and nausea. The disease lasts from a few days to several weeks. In a few cases the Salmonella bacteria can enter the bloodstream and result in a general infection.

There are many different types of Salmonalla. In pigs the most common type is Salmonella Typhimurium. The pigs often have no disease symptoms although they harbour the bacteria in their intestine.

The industry has, in cooperation with the authorities, started an action plan with a view to reduce the incidence of Salmonella in Danish pig meat. All herds supplying more than 200 pigs for slaughter annually are regularly examined for Salmonella based on meat samples taken at the slaughterhouse. The occurrence of Salmonella in fresh pork is also examined continuously. Salmonella is here found in 1-2% of the samples.

This work, and other efforts, has resulted in a reduction of human Salmonella infections over a number of years.

Resistant bacteria
A special problem relating to pathogenic bacteria is the risk that they can develop resistance against antibiotics. This can occur if the same type of antibiotics is used to combat the bacteria in both animal husbandry and for humans. The consequence could be that it becomes more difficult - or even impossible - to combat pathogenic organisms in humans. This risk has led to a ban against using the antibiotic growth promoters avoparcin and virginiamycin and a voluntary stop for the use of antibiotic growth promoters in Danish pig production from 2000.

Salmonella DT 104 is especially in focus because it is resistant. If DT 104 is found in a herd there are special precautions to ensure that the infection isn't spread to other herds. There are also special precautions for slaughter and use of the meat to ensure that the bacteria do not come out to the consumers.

Yersinia
The bacterium Yersinia enterocolitica can cause gastrointestinal infections in humans. Pigs are probably the most important source of infections inDenmark. The bacteria are killed easily by heating - 2-3 minutes at 60oC are enough - so the majority of cases are probably due to cross infections, i.e. infection from raw meat for example via cutting boards, to other foods that are eaten raw, for example salads. The incubation period (the time from infection to disease outbreak) is 1-11 days. The typical symptoms are acute bloody diarrhoea and fever. These symptoms are most often seen in children below the age of seven; in older children severe stomach pain can occur. This can be confused with appendicitis. Subsequently to an infection rheumatic joint inflammation can develop. The number of registered Yersinia infections in humans has fallen over the recent years.

Listeria
The bacterium Listeria monocytogenes can cause serious disease, for example general blood infection, meningitis and abortion. Only a few Listeria infections are registered, but because the disease can cause death, it is considered very seriously. Listeria occurs everywhere in the surroundings and can be transferred to foods. The main way to avoid this is meticulous hygiene. In the meat area the efforts against Listeria are concentrated on products that are not heat treated further prior to consumption, e.g. cold cuts.

Trichinella spiralis
Trichinella spiralisis a small worm (1.5-4 mm long), which can infect many mammals and birds. They occur particularly in wild carnivores (foxes, bears, lynxes etc.), but also in some omnivorous animals such as wild boars and rats. They can infect domestic animals, e.g. pigs and horses plus humans. The trichinae live in the intestine; from there the larvae move into the blood vessels and the organs, e.g. the diaphragm plus the chewing and tongue muscles, where they encapsulate. The infection is transferred when animals or humans eat trichina-infected meat. The typical symptoms of trichina-infection are muscle pains, particularly in the breathing, eye and chewing muscles, plus oedema in the face. Consumption of a large number of trichina-larvae can cause death. Infection of pigs can occur via rats, or when they eat for example a fox carcass. Trichinae have not been found in Danish pigs since 1929.

Residues
'Residues' mean occurrence of unwanted compounds in the meat. It can for example be drug residues, pesticides or heavy metals. The compounds can originate from the feed, veterinary treatment, the equipment or the surroundings.

In Denmark there are statutory regulations about feed composition. Feed companies are controlled by the Danish Plant Directorate and the results are published regularly.

Medical treatment of sick animals may only be done by a veterinary surgeon; however, the farmer may take responsibility for the treatment, if he has a health advice agreement with the veterinarian. Medicine may only be given for treatment of diseases diagnosed by the veterinarian. Preventative treatment is thus not allowed. The veterinary surgeon must ensure that the farmer knows the withholding periods (i.e. the time interval between treatment and supply for slaughter) in connection with medical treatment of sick animals. Hormones are generally forbidden and have never been permitted in Denmark.

The Danish Veterinary and Food Administration checks for residues in fresh meat. The following categories are included:

Drug residues
During the last ten years spot checks for antibiotic residues in Danish pig meat have found residues in between 0.01 and 0.04% of the examined samples (19,000-22,000 samples annually).

When residues of antibiotics are found, the Veterinary and Food Administration evaluates whether there is an infringement of the drug laws. The chief veterinary officer visits the herd, and possibly also the relevant veterinary practitioner, and produces a report about the use and supply of antibiotics in the herd. The Danish Veterinary and Food Administration then decide whether the matter is to be transferred to the police with a view to charging the pig producer.

Hormones
During the last ten tears spot checks have also been made for residues of hormones in meat. Residues of hormones have never been found in Danish pig meat.

Pesticides and PCB
It is not permitted to use pesticides containing chlorine and PCB in animal husbandry in Denmark (e.g. for fly control) or in rooms where food, grain and feeds are produced or stored. Among this type of pesticides, only DDT, dieldrin and lindane have been permitted up to the 1960s.

During the last twenty years the Danish Veterinary and Food Administration have carried out spot sampling for residues of pesticides and PCB in foods. Spot checks from pigs have, for a number of years, only shown traces of pesticides and PCB. The maximum permitted levels have thus at no time been exceeded. The traces of these compounds are due to their very slow degradation in nature.

Heavy metals
Spot checks for residues of heavy metals in meat covers lead, cadmium, mercury, nickel, selenium and chrome.

Over a number of years only one sample has exceeded the maximum permitted levels for heavy metals. The contents of mercury and selenium have been very stable the last ten years; the contents of cadmium, lead, nickel and chrome have been falling.  

Ensuring food safety
The maintenance of a high level of food safety in Danish pig meat is ensured as result of a considerable effort by the authorities and the industry in all stages of the production. The authorities are for example controlling feeds for Salmonella and the meat for diseases and residues. The industry and the authorities have joined forces in creating an action plan aimed at reducing Salmonella in all stages of the production. At the slaughterhouses the industry has implemented self regulation of hygiene plus an effective system for tracing products back from the consumer to the primary production.

Slaughter methods and training
A number of new slaughter techniques have been developed in recent years for further improvement of the hygienic quality. A common feature is to avoid cross contamination - i.e. that contamination is transferred between carcasses for example via equipment or persons.

Rapid chilling of the carcasses also contributes to limiting the bacterial growth. The regulations demand that the core temperature must be reduced to a maximum of 7oC quickly after slaughter and thereafter maintained at this temperature. This is ensured by having constant temperature monitoring and by having sufficient cold rooms where carcasses and meat is kept cooled.

Buildings and equipment
The design and maintenance of the slaughterhouses are also important in order to avoid contamination of the meat with bacteria, foreign bodies etc. from buildings and equipment.

The veterinary inspection continuously checks the maintenance of the buildings and equipment. It is also checked that there is a reasonable and even flow through the plant. This ensures that cross contamination between different products (e.g. raw materials and heat treated products) is avoided; it also ensures that no meat becomes too old.