ZOONOTIC MICROORGANISMS ASSOCIATED WITH MEAT INDUSTRY

~Dr S.George 1*, Dr A.J.Nath2 and Dr S.S.Deka3

 

The history of contact between human and animals has always involved infectious diseases, and today almost half of the emerging infectious diseases are of zoonotic origin. The problem is viewed as an infectious animal reservoir that poses an infectious risk to humans—either through direct contact with infected animals and their excretions, meat, milk, or other tissues, or via a vector transmission bringing the pathogen from the animal population into human hosts .There are several diseases well known to both the industry and the general public, that are directly related to the domestic meat species of beef, pork, lamb, and poultry. The meat industry is vulnerable to a variety of infectious diseases that can manifest in food processing areas mainly due to poor personal hygiene and processing, sanitation practices, which in turn can develop the growth of bacteria, viruses, moulds, and yeasts. Some of the bacteria are known to originate from meat; others can and develop in food processing areas through unhygienic practices. These can then set the stage for:

Foodborne infection, such as Salmonella or Trichinosis, caused by ingesting food that is contaminated with bacteria, parasites, and viruses.

Foodborne intoxication, either bacterial, such as E coli 0157, or chemical, where food has been contaminated with toxic chemicals, such as cleaning compounds or pesticides.

Therefore, meat workers especially need to know about these infections viz. Leptospirosis, Anthrax, Brucellosis, BSE (bovine spongiform encephalitis) Campylobacter, Salmonellosis, Cryptosporidium, Orf, E.coli ,Trichinosis, Scrapie etc.

Many animals can carry the leptospirosis bacteria including cattle, bobby calves, pigs, sheep, lambs, dogs, goats and deer. Rats can also spread it. These animals shed leptospira in their urine. Infected animals may not look sick even while they are shedding the leptospira bacteria in their urine. Humans tend to get leptospirosis when infected animal urine, or water contaminated with urine, gets in their eyes, nose, mouth or through cuts or cracks in their skin. Just a splash or spray of urine can spread the disease. Leptospirosis bacteria can survive for days after an animal has been killed, e.g. in chilled kidneys. Anyone working in and around a meat plant, including maintenance workers and other visitors, may be at risk. Meat workers are mostly at risk of catching leptospirosis when hosing down yards or other areas, tumbling pig carcasses removing hides or pelts, taking out the urinary bladder, handling gut contents, working with kidneys, handling offal for pet food, working in the rendering area etc. Leptospirosis can be like a very bad case of the flu, with headaches, fever or chills, nausea or vomiting, and weakness. Leptospirosis will make some people seriously ill, needing intensive care at hospital and have lasting kidney or liver damage.

Another important infection associated with meat industry is Anthrax. Anthrax can be an occupational disease of workers who process carcasses and hides of infected animals, including farmers, abattoir workers, butchers, and workers in factories that process hides. Veterinarians who handle sick animals are also at risk, as are laboratory workers who routinely work with B. anthracis. The Anthrax organism forms spore as soon as the carcass of infected animal is opened. These spores  are very resistant and can survive in the environment for almost 20 years. Cases of both inhalation and cutaneous anthrax have developed in travelers and drum makers who have bought drums or hides originating from infected animals. Accidental ingestion of Anthrax spores can result in intestinal form of anthrax. In the 2001 intentional use of anthrax in mail for bioterrorism was used, where postal workers were an occupational risk group. In 2007, two cases of cutaneous anthrax in Connecticut were tied to importation of infected goat hides for drum-making.

Brucellosis is another occupational disease of developing countries or poor rural regions of the developed world. In endemic regions, the principal pathogen implicated is B. melitensis. Infections are typically acquired through the consumption of dairy products, especially non-pasteurized goat’s cheese and untreated milk. Evidence does not support human to-human transmission, except in rare cases of infection via bone marrow transplantation, blood transfusion, and a possible case of transmission to a sexual partner via the organism in semen. Women develop more severe brucellosis with more articular involvement and more severe thrombocytopenia with B. melitensis infections.

abortusis the second commonest species infecting humans, and is typically an occupational disease in abattoir workers, butchers, veterinarians, and farmers, usually affecting adult men, who become infected either through the oral, respiratory or conjunctival routes or cut wounds. Ingestion of dairy products constitutes the main risk of infection to the general public apart from handling of aborted materials to the farmer and veterinarians. Brucellosis is readily transmissible to humans, causing acute febrile illness known as undulant fever. The fever may be accompanied by malaise, anorexia and prostration and may last for months together. The fever may progress to a chronic form and can also produce serious complications affecting the musculoskeletal, cardiovascular, and central nervous systems.  In man, brucellosis diagnosis is almost always missed because other diseases that partially or almost totally mimic brucellosis symptoms including malaria, typhoid, paratyphoid and influenza.

BSE(bovine spongiform encephalopathy)

 commonly known as mad cow disease, a fatal brain-degenerative disease (encephalopathy) in cattle that causes a spongy degeneration in the brain and spinal cord. BSE has a long incubation period, about two-and-a-half to eight years, usually affecting adult cattle at a peak age onset of four to five years. All breeds are equally susceptible. The cause is cattle, which are normally herbivores, being fed the remains of other cattle in the form of meat and bone meal (MBM), which causes the infectious agent to spread. The disease can easily be transmitted to humans who eat food contaminated by the brain, spinal cord, or digestive tract of infected carcasses. The infectious agent, although most highly concentrated in nervous tissue, can be found in virtually all tissues throughout the body, including blood. In humans, it is known as the variant Creutzfeldt-Jakob disease, and as of June 2014 it had killed 177 people in the United Kingdom and 52 elsewhere. People and animals may be carriers without showing any symptoms.

Campylobacter, Salmonella and Cryptosporidium are three bugs found in a range of animals and food from animals. These infections are often described as food poisoning. The illnesses are much worse than a normal ‘tummy upset’ and in a very small number of cases, can be fatal. These bugs can all be avoided if we have good personal hygiene at work and at home. We can get infected with these bugs if we don’t wash our hands after going to the toilet, after handling raw poultry or raw milk or after handling pets or farm animals, especially dairy cattle and calves. The bugs can get into our mouth from our fingers, food, smoking or even wiping our face. Salmonella will make us feel ill more quickly (½ – 3 days) than Campylobacter (3 – 5 days) and Cryptosporidium (2 – 7 days). Salmonella is a foodborne bacteria with 1,300 types known. One of the most severe infections caused by salmonella is typhoid fever. The main sources and carriers of salmonella in the food industry are mostly poultry, eggs and cracked eggs, shellfish, raw milk, and service workers with unwashed hands. With salmonella, a small number of people can get sore joints, irritated eyes and suffer painful urination that can last for months or years. It can also lead to chronic arthritis. Cooking products to an internal temperature over 60°C (140°F) for 12 minutes can kill Salmonella. There can be some long term effects, too. With Campylobacter, the abdominal cramps sometimes continue and relapses can occur. In most healthy people, a Cryptosporidium infection produces a bout of watery diarrhea and the infection usually goes away within a week or two.

Orf is a skin disease that occurs both in people and animals. In sheep, orf is usually called ‘Scabby Mouth’ is caused by a virus. Orf is most commonly seen in people who come into contact with infected sheep and lambs, such as farm workers and meat workers. The virus can also be caught from goats and deer. The orf virus enters the body through a break in the skin such as a cut, scratch, blister or burn. The virus is very hardy and may persist on animal skin or wool. It can also be transmitted by contaminated knives, shears, stalls, trucks and clothing. A small raised spot (like a pimple) appears around 3– 6 days after contact with the virus. The spot grows larger and become surrounded by a pale ring that turns red. The red spot then becomes weepy and develops a crust before it dries and forms a scab, under which the skin starts to heal. The sore is more irritating than painful and may feel prickly. Complications are rare, but sometimes a rash can occur all over the body. Symptoms may last for 3 -6 weeks.

Clostridium botulinum an anaerobic microorganism which forms spores that exist over a wide range of temperatures. The organism itself does not cause illness, but the toxin it produces is one of the most deadly known to humankind. The spores can survive in frozen, raw, and precooked food. Although it is not a frequent cause of illness, it is considered the most serious to deal with in the food industry. This nasty organism is found in the intestines of humans and animals and in soil and streams. The major source of botulinum is swollen and damaged canned products and/or air-tight packages such as vacuum-sealed products with low acid foods such as beans, fish, and meats. The spores of the organism are very heat resistant and can survive boiling temperature.

Clostridium perfringens is  another anaerobic organism that produces heat-resistant spores. It also grows in the danger zone of 4°C to 60°C (40°F to 140°F) and may double in numbers in 10 minutes. This bacterium is found in intestinal tracts of humans and animals, in sewage, and in manure. Insects and rodents can also become contaminated. Unwashed hands and dirty clothing are major sources and carriers of the disease. The main food sources affected by C. perfringens are foods high in proteins such as fresh meat of all types and cooked meats like stews and gravies that have cooled too slowly.

A bacterium found naturally in the intestines of humans and animals is E.coli. The strain common to the meat and food industry is E. coli 0157:H7. E. coli does not cause a disease and is not considered parasitic because its source of food is the body waste in the intestinal tract. However, should E. coli gain access to the kidneys, bladder, or other internal organs, it can become parasitic and produce infections that can turn fatal. E. coli outbreaks associated with domestic animals have strained the meat industry when it has been discovered in ground meat supplies. In addition, E. coli has occurred in milk, cheese, and related foods as well as in plants and plant products irrigated with contaminated groundwater supplies.

Listeria monocytogenes is commonly found in soil, stream water, sewage, foods made from milk, and processed foods such as hot dogs and deli meats. It can also be found in uncooked meat and vegetables and fruit such as apples and cantaloupes. Animals can also be carriers. Contamination may occur after cooking and before packaging. Listeria is responsible for listeriosis, a rare but potentially lethal foodborne infection. Listeria can grow in temperatures from 4°C to 37°C (40°F to 96°F), which is human body temperature. The bacterium is known to cause meningitis, a potentially fatal disease.

Staphylococcus is an aerobic organism which causes food poisoning by releasing toxins into food. It can survive for months in the soil and in a frozen state in food. The most common carrier is the human body, particularly through skin abrasions, wounds, infected sinuses, pimples, etc. Raw poultry is also known to be a carrier. Food poisoning usually occurs when already cooked or easy-to-eat food is re-contaminated with staphylococcus. In the food service industry, susceptible products are those high in protein, such as meat and meat products (especially chopped meats), chicken salads, and cheeses. Staphylococcus can grow to enormous numbers on meat without producing changes in colour, odour, or taste, if the infected product has not been stored in the safe temperature zones below 4°C or above 60°C. Another important aspect of Staphyloccus contamination of meat is to consider the chances of acquiring Methicillin resistant Staphylococcus aureus (MRSA) infection. MRSA may transfer its antibiotic resistance property to other microbes, further contributing to the spread of drug-resistant bacteria. To avoid infection with potentially contaminated meat, people should wash their hands after handling raw meat and cover cuts or open wounds on their hands by wearing gloves and finally cooking meat thoroughly to kill the bacteria.

Trichinosis: a disease caused by Trichinella parasite that initially enter the body when meat containing the Trichinella cysts (roundworm larvae) is eaten. For humans, undercooked or raw pork and raw dry cured pork products, such as pork salami, have been most commonly responsible for transmitting the Trichinella parasites. Trichinosis is a foodborne infection and is not contagious from one human to another unless infected human muscle is eaten. However, almost all carnivores (meat eaters) or omnivores (meat and plant eaters), such as bears, can both become infected and, if eaten, can transmit the disease to other carnivores and omnivores. In rare instances, larvae in cattle feed can infect cattle. There are six species that are known to infect humans. Curing (salting), drying, smoking, or microwaving the meat does not consistently kill infective larvae. Proper cooking of meat can eliminate the risk of infection.

After realizing the importance of these harmful diseases, we can always follow some simple steps to protect us from above infections

  1. Always wear protective clothing, safety glasses or visors, waterproof gloves and boots while working.
  2. Carefully wash hands and forearms before eating, drinking, smoking or touching the lips, face or eyes or smoking.
  3. Don’t eat chicken, pork, mince or sausages unless they’re well cooked and there’s no pink meat.
  4. If you’ve had raw meat, chicken or sausages on a chopping board or bench, make sure it’s washed before any other food goes on it
  5. Don’t leave uncooked food or leftovers sitting around, cover it up and put it in the fridge.
  6. Always cover cuts, wounds and scratches.
  7. If your face gets splashed with urine, blood, etc wash your face immediately.
  8. Report any flu-like illness to your doctor and remember to mention that you’re a meat worker.

 

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Authors: 1*&2Department of Microbiology & 3Department of Physiology & Biochemistry, Lakhimpur College of Veterinary Science Joyhing, Assam Agricultural University, Lakhimpur, Assam,*CorrespondingAuthor’s Email:shineygeorge0@gmail.com


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