## 1 Introduction  
Meat is a highly nutritious food rich in proteins, lipids, vitamins, and minerals. Nevertheless, chemical substances and microorganisms might reduce the nutritional quality of meat and its products [1]. These spoilage factors produce toxic substances in meat products that are hazards to consumers' health [2]. Spoilage of meat and meat products because of lipid oxidation and microbial multiplication have undesirable effects on the nutritional quality and result in tremendous economic losses [3]. Moreover, the activities of microorganisms might also have negative effects on the quality of meat due to the development of undesirable reactions that involve bad odour, colour, and textural changes in meat products [4]. Therefore, preservation of meat through antioxidants and antimicrobial agents plays an indispensable role, resulting in consumers buying safe and high-qualitymeat and meat products. Meat preservation also inhibits lipid oxidation, activities of enzymes, and the proliferation of spoilage and foodborne microorganisms that result in economic and nutritional losses in the meat processing industry [5,6].  
The utilisation of antioxidants is seen as a useful strategy in delaying or retarding lipid oxidation as well as inhibiting the generation of toxic oxidation products in meat products, thus enhancing the shelf-stability of food products [7,8]. At present, most consumers prefer processed meat products that are chemical preserving-free because of safety issues as well as health-related risks [9]. Moreover, utilisation of synthetic preservatives in meat products have proved ineffective in completely delaying spoilage microorganisms or preventing important foodborne pathogens such as _Listeria monocytogenes_[10,11]. This explains the meat industry's renewed interest to search for natural antioxidants from plant extracts. The inclusion of natural antioxidants not only improves the shelf stability of meat products by delaying lipid oxidation because of polyphenolic compounds, but also enhances the physicochemical, textural, and organoleptic properties of meat products [12,13]. Therefore, the use of plant extracts that are rich in polyphenolic compounds enhances the quality and shelf life of meat products [14,15].  
_Moringa oleifera_, which is customarily known as horse radish tree or drumstick tree, is regarded as a possible functional ingredient and auspicious source of natural antioxidants [16]. Almost all parts of _Moringa oleifera_ (MO) plant such as roots, seeds, seed oils, leaves, and flowers have been utilised on a large-scale basis as food or components of medicine [17]. In addition, the leaves contain considerable amounts of antioxidant vitamin A, C, and E; protein; carotenoids; tocopherols; total phenols; and minerals such as iron, magnesium, potassium, and copper [18,19]. The leaves, therefore, have demonstrated their potential to be utilised as a functional ingredient in meat and its products such as ground meat and patties.  
However, the use of MO as a non-synthetic preservative in ground meat is very limited. The powder of MO leaves might be a good choice in the production of healthier ground beef. This may also add value to the local production of the MO plant. Moreover, the nutrients in _Moringa oleifera_ leaves powder (MOLP) could be conveniently concentrated because of the drying process, thereby improving the shelf life, handling, and storage of MOLP [20]. The presence of polyphenolic compounds in medicinal plants such as MO is associated with its preservative effect [21]. In light of this, the aim of this work was to produce ground beef fortified with MOLP and to determine the influence of its inclusion on the nutritional properties, lipid oxidation, and growth of microorganisms in the formulated ground beef.