Today I was lucky enough to get to work with a vet at Norways larges abertoir for svine in Steinkjer. Nortura Steinkjer abertoir slaughter about 220 000 pigs a year. In addition is the abertoir rented to slaughter about 55 000 pigs from Spis Grilstad. So all in all they slaughter almost 300 000 pigs pr year. There are about 200 people working at the factory.
When I came to the slaughter factory I was greeted by the vet Maren Meldal. She was going to show me here usual tasks and the factory for the day. We started off in the dressing rooms where everyone got new, clean clothes every day. I was given white trousers, a white t-shirt, white clog and a green coat. We walked from the changing rooms down a hallway and to a safety stop where the green coats were removed along with the clog. Then you stepped over a line from the unclean area to the clean area. In the clean area you were given a new pair of clog and hair covering. The clog were washed and our hands washed before we had hand sterilizer on. Then we got to step into the actual slaughter house. There were several vets working at the factory every day. They had routines so that they wouldn’t do the same thing all day. She started by showing me around the whole factory explaining each step in the process
The pigs are transported to the slaughter house, where the vet inspects as they walk off the lorry. This is in case some of them are injured during the transportation, in which case they would be taken to the side so that the pig wouldn’t have to walk all the way around the farm before reaching the euthanization station . The other things the vet would check for was umbilical hernias. Hernias up to a handball size 15cm and without wounds would be ok, but larger than this, the pig would have to be in a separate pen so that it wouldn’t get trampled. The vet told me that even small hernias would sometimes be trampled. The vet would sign a blackboard over each pen signalizing for the workers that the pen was cleared for further processing. Each of the pens had water nipples incase the animals happened to stay there over night. The animals seemed very relaxed and would show this by laying down even 10 minutes of walking of the truck.
The next part of the process was the anaesthetizing / euthanization. The optimal method would need to be without force, with immediate loss of consciousness. 100% safety. Long lasting and without any affect of the meat quality. No method today will fit all these demands.
|Bolt Gun||Electric||CO2 Gas|
|Risk of waking up||Low||High||Low|
|Meat quality||Ok||Not optimal|
C02 gas as an anaesthetizing and euthanizing method is only approved on pigs and large ruminants. Electric is approved for all animals, but with electric anaesthetizing on large ruminants there is a demand for it to give heart arrest. The bolt gun is also done on all, but is less suited for pigs because of powerful cramps which makes it hard to kill them with knife and it also effects the meats pH. No matter the method the animal will die because of the lack of 02 because it’s drained of blood, which will give heart fibrillation. 85% of traditional anaesthetizing and euthanizing of pigs are done by group gas. The negatives with using CO2 gas is that the animals can experience pain, anxiety or unease. The pigs will loose the consciousness after 15s depending on the concentration of the gas. It could cause hyper ventilation because of the gas and some could shake and kick violently for 15-39 sec after it’s been lowered down into the gas. The positives about using gas are that you don’t have to fixate the animals and that they walk voluntarily into the chamber, before being lowered down into the gas. The main positive point is that many people think that gas causes strangulation because of lack of 02, but the actuality that I learned is that the gas CO2 causes a lowering of the pH in the brain cells which causes the animals to pass out.
I asked if it was safe for the people standing at the top of the well, but the CO2 gas is heavier than 02. That is why the pig is lowered down where the CO2 gas is more concentrated. The lower the concentration of gas in the well the longer they would have to spend down there for it to have an effect. This factory had a computer that made sure that the gas concentration had a minimum of 87% of CO2 down in the well. If the % went under this the production would stop until the levels had risen again. With a % of 80-90% most pigs will actually die in the gas and like I said before will pass out after 15 seconds. The pigs are lowered down and the whole circulation takes 3-5 minutes. The CO2 diffuses through the blood of the brain through the blood-brain barrier and react with water molecules to HCO3– & H+. This causes the pH to decrease below the normal 7.4 to 6.8 and the animal to pass out. For the animals that doesn’t die in the gas could wake up minutes later if they aren’t bleed. Bleeding is done within 60 seconds of stunning so there is insufficient time for recovery to take place before there is irreversible loss of brain function from lack of oxygen. In order to ensure a rapid bleed out, the major vessels must be severed properly. The chest stick method is the best method to ensure a good bleed out. The operator should ensure that the animal is dead by checking for the absence of the brain stem reflexes (blinking when cornea is touched and reflexive gasping breaths).
Once the animals are hung up by their feet and bleed out. They are transported to a washer that wash the pigs with big brushes kind of like a car wash. The back hairs are removed before the bodies are flamed so that any other hairs are burned off.
The next part of the line was to suction out fat along the ribs and abdomen. Then there would be something they called trikin tests. Trikiner is a parasite Trichinella spp that can be seen in meat. People could become infected by this nematode if the meat isn’t boiled or cooked correctly. They would cause muscle pain and high fever, with no effective medicine. The occurrence of these are very rare today, but still every pig are tested to be on the safe side.
The ear, tail and feet are then removed. The stab wound is cut out along with the head, kidneys. The carcasses is then stamped 5 places to ensure each portion that its cut into gets a stamp with the factory and Norwegian logo. Each carcass is weighed and marked that it’s ok for meet consumption. The carcasses then goes over to a large cooling room, where it takes them 24 hours to pass through before reaching to bone removal/ meat portioning stations before they are packed (some with frozen ice) and transported to the stores. In the cooling room they aim to get the carcasses down to 4°c as fast as possible and the sows to 7°c. Each of the stations up to the cooling is done by humans which uses a 2 knife system with a sterilization container, to make sure that there are no contaminations between the carcasses. They also along with changing knifes between each pig, wash their hands of blood. The sterilization contained had 87°c.
I was with the vet, so we were placed at the inspection station. We got all the pigs that had something wrong with them. It was incredible to see that all the anatomy we have had the past 2 years came to use. The vet just said, look for the normal, because then It would be easier to spot the un-normal. If the pig had a tail bite or tail wound we would cut along the spine for abscesses which were cut out along with that part of the spine. If there were more than 2 abscesses the carcass would be sent away as waste, not suitable for human consumption. Each carcass came with its heart, lungs and liver, so each heart was cut open to look for endocardits in the heart valves.
Endocarditis occurs when germs enter your bloodstream, travel to your heart, and lodge on abnormal heart valves or damaged heart tissue.
The lungs would be checked for chronic or acute respiratory disease. If acute the animal would be disposed but chronic would be ok because it would be encapsulated infection.
If there were any tail bites or wounds the carcass hip joint, between ribs and sternebrae would be checked for capsulated pus. The lymph nodes would be checked to see if they were enlarged and if there were any damage to the joints, either with pus or just normal swellings that part would be removed. If more than one lump of capsulated pus was detected the whole carcass would be disposed of, but if only one that “lump” would be cut out and the carcass would continue on with a note on it.
Later that day they had taken a test of 8 pigs and 2 sow kidney to test for traces of antibiotics. All meat in Norway has to be without traces of antibiotics by law. Sick pigs often get treated by antibiotics and are then kept 14 days after end of treatment before slaughtered, but some farmers will try and send them off before. The kidneys is the place in the body where antibiotics are gathered up and is therefore used to test for traces. It is very rare that they detect any traces. A positive test result would result in the carcass being disposed off. In the test both kidneys were collected to have a back up kidney in cases where the test comes out positive to verify. The top layer of one of the kidneys are burned and the top layer is removes. Then a sample of the cortex and medulla of the kindey are taken out 5x5x10 mm, and put in 3 separate Peteri dishes each with a different type of antibiotic. Once that is done with all 10 samples the samples are left in room temperature for 1 hours before incubated in 37°c for 18 hours. On other days they could take samples to test for salmonella as well.