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A PhD just about biltong for Maxine
Author: Engela Duvenage
Published: 13/03/2017

Researcher focused exclusively on how to make biltong for her doctorate; that will be awarded on 14 March.

When Maxine Jones receives her doctorate in Food Science from Stellenbosch University (SU), she will achieve a unique first that is distinctly South African:  she will receive a PhD for research focusing exclusively on how to make good quality biltong.

In the process the 27-year old can say she developed a scientifically proven recipe for making consistently delicious biltong.

Her parents, June and George Jones, share her love of biltong. They are now enjoying the direct benefits from all of her hard work. This Capetonian who matriculated from Wynberg Girls' High handed over her recipe to her parents so that they can make biltong themselves. In the process they are now assured that their own private stock of dried meat is of a consistent good quality.

Maxine will receive her doctorate in Food Science on 14 March 2017 from Stellenbosch University's Faculty of AgriSciences. Her industry-based research project focused on different aspects of biltong processing, such as the use of standardised drying procedures to dry the meat at best. She took note of factors such as temperature, humidity and air movement. She also investigated the presence of different yeasts, moulds and even bacteria that often occur on biltong, and that play a role in its shelf life.

"Quality and consistency is important to both the consumer and the biltong industry," says Maxine, who believes the local industry needs to standardise drying guidelines to ensure more consistent quality and to sidestep food safety issues. "There are currently no processing guidelines for biltong production in South Africa, and this leads to vast differences in the end product."

"The biltong industry has become an economically important sector in the South African meat industry and has the potential for further growth, both nationally and internationally," she adds.

Maxine also investigated export opportunities that are available to South African producers, and the certification processes and laboratory guidelines that they need to consider.

A career in meat

Maxine knows her way around a good cut of meat. This is because learning how to debone and process meat into salami, polonies, biltong and bacon, is part for the course when SU postgraduate students do meat-related research under the guidance of Prof Louw Hoffman of the South African Research Chair in Meat Science: Genomics to Nutriomics in the Department of Animal Science. Theirs is a small yet tightly knit research group.

"Our small research group is involved in several trials per year, and we all pitch in to help in one another's projects. We are therefore involved in the whole process, from the hunting of the animals in some cases, to sample collection and trial setups," explains Maxine, who says that team work formed an integral part of her postgraduate studies. "You learn to work in difficult circumstances, outdoors and with the minimum amount of equipment."

Her research path crossed with biltong during her MSc studies. Her research involved testing the addition of rooibos tea extract to South African droëwors as a natural antioxidant in an effort to increase the shelf-life of the product. "It also adds a traditional South African spin to this well-known product," she adds.

Her field of research has subsequently landed her a job as the quality and food safety manager for Cape Deli Biltong in Cape Town.

Her research has also taken her places, from Namibia and the Wageningen University in the Netherlands to an international conference in Thailand. She even travelled to Reunion Island, a remote French territory near Mauritius. There she tested the spicing of biltong with ultrasonic equipment and its subsequent drying. The equipment was available at the Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), with which Stellenbosch University's Department of Animal Sciences enjoys ongoing cooperation.

"Biltong isn't such a simple matter as we may think; there's a science behind it," says Maxine. "With the increased popularity of biltong the research opportunities are vast, and this research is just the beginning of things to come."

Key findings

In the course of her project, Maxine consistently dried biltong at temperatures around 25°C, at a relatively low humidity of 30%, and an air speed of about 0.2 meters per second. Here are some of her findings:

  • Adding vinegar in the salting/spicing step of beef biltong did not increase the time that the meat takes to dry out. Therefore, adding vinegar does not make meat dry faster.
  • Vinegar does however help control the levels of microbes on biltong for at least a month after production. It therefore has an influence on shelf life.
  • Overall, it is useful to add vinegar in a spice formulation to ensure a consistent product that is safe for consumption.
  • Drying rates depend on the type of meat muscle being used, and also the source of the meat. Given the specific parameters used throughout the study, gemsbok topside took 76 hours to dry, fatty beef topside 118 hours, while beef topside and silverside both required about 96 hours to dry.
  • Yeasts and moulds, which often cause a problem during storage, generally become visible after six weeks. Although not visible to the naked eye, they can already be present in high levels at the end of drying.
  • Weight loss or adding vinegar does not influence the salt content of the dried meat.
  • Beef biltong without vinegar has a pH of 5.56 to 5.75, while the addition of vinegar to biltong lowered its pH to 4.89 to 4.93, which prevents the growth of microbes.

Reference: Jones, M.S. (2017). Profiling of traditional South African biltong in terms of processing, physicochemical properties and microbial stability during storage. DPhil (Food Science), Stellenbosch University, March 2017.