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Parasite insight could curb infections and limit waste

Connecting food safety and efficiency – Matthys Uys, MSc Food Safety student, shows how the fight against a worm can reduce waste where it is most needed.

If you’re like most people, you probably haven’t heard of or thought much about tapeworms - perhaps you’re aware of the ill-advised suggestion of ingesting these parasites to lose weight.

However, these strange and slightly gross creatures are surprisingly intriguing, and have developed intelligent avenues to ensure they find a cosy home inside an unsuspecting human.

For example, the beef tapeworm - Taenia saginata - infects people by an indirect route, first lodging itself in the muscles of cattle in its intermediate form, where it is visible as small cysts.

When a person ingests undercooked beef containing these cysts, the worm develops in the human’s small intestines. Here it will go about releasing eggs which are shed via the stool into the environment.

These may infect grazing cows, developing into muscular cysts with the primary aim of being ingested by an oblivious consumer. Clever, won’t you agree?

Man with cattle on an unpaved road surrounded by trees.

Preventing infection

This parasite occurs throughout the world, and since we do not want people to go around being infected with tapeworms, the natural question is: how is this prevented?

The most important method is by meat inspection. At every abattoir where meat is produced, carcasses undergo mandatory inspection by trained personnel, who make cuts in particular locations on the carcass to look for these cysts.

When spotted, these serve as confirmation that the animal was exposed to tapeworm eggs and that there may be cysts elsewhere in the carcass.

The meat then undergoes freeze or heat treatment to kill the parasite in its intermediate form, preventing human infection, and stopping the further spread of this disease in people and cattle.

When a carcass is found to contain significant numbers of cysts, all the meat from that carcass is rejected for human consumption.

Although this may seem simple enough, the tapeworm also has consequences other than the stomach aches and mild nausea it causes in people.

Looking for cysts by making cuts into the meat reduces the proportion of the carcass that can be used and leads to significant wastage.

Furthermore, when an infected carcass undergoes treatment, this reduces the value of the meat and the price that the farmer is paid for it.

When an entire carcass is rejected due to heavy infestation, the financial and food loss is enormous, especially considering the time and financial investment that raising each animal requires.

This is made worse by the fact that the disease is especially prevalent in developing countries where resources are often scarce, beef is an essential protein source, and many cattle producers are small-scale or upcoming farmers. Every gram of meat is therefore precious and should be preserved as far as possible.

Inspection research 

I carried out research at the largest beef abattoir in South Africa, looking at ways to increase the efficacy of inspection for this common parasite, while reducing food waste.

I did this by studying the impact of making additional incisions into the heart muscle during inspection to see if this increased the number of positive cases found. The heart is inexpensive and mostly used in processed meat, and so cutting it doesn’t reduce the overall carcass value or available food.

I also assessed the benefits of making a specific cut into the shoulder muscle, which forms part of the inspection only in African countries.

This muscle is a valuable part of the carcass, and therefore an incision here reduces the overall use and value of the meat. It is not done anywhere else in the world for exactly this reason.

The study produced exciting and meaningful results. The additional incisions into the heart picked up significantly more positive carcasses, meaning this simple technique costing very little can reduce the prevalence and spread of the disease in both humans and animals by identifying more cases and breaking the cycle.

Furthermore, the cut into the shoulder did not significantly assist in the detection of cysts, meaning that it should be removed from the inspection technique currently mandated in many African countries.

Doing this will reduce food waste, increase the amount of meat that can be utilised in every carcass, and improve the financial reward to the farmer.

In carrying out this work, I have learned that one of the joys of science and research is the crossover of multiple disciplines that are connected in some way or another.

My pursuit of an MSc in Food Safety at the Global Academy of Agriculture and Food Security provided me not only with the wealth of knowledge required to manage relevant food safety issues, but it also allowed me to undertake research that could make a real difference in areas where it is most needed.

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MSc Food Safety

Image credit: Bill Wegener on Unsplash