# Microbial Growth Dynamics in Minced Meat Enriched with Plant Powders
## 1 Introduction  
Meat and meat products contain valuable nutrients for human consumption; meat is an excellent source of protein, phosphorus, zinc, and iron [1]. Since raw minced meat is an easily perishable food, it is a suitable material for evaluating the inhibitory effect of various plant additives and their blends on microbial growth in the food matrix. European Commission Regulation No 2073/2005 for microbiological criteria in foodstuffs establishes criteria for aerobic colony count in minced meat [2]. According to the process hygiene criteria, the maximum number of aerobic mesophilic microorganisms can be 6.70 log cfu/g for two subsamples and 5.70 log cfu/g for three subsamples. These numbers will be considered when discussing the microbiological quality of the raw minced pork samples in the present study. The total viable count of microorganisms is often used in food durability studies to assess the microbiological quality of food within the determined time period. Enumeration is one of the most commonly used forms of bacteriological analysis in food microbiology [3]. Various food preservation methods and technologies, such as modified atmosphere and vacuum packaging, marinating, and the use of preservatives are applied to enhance the safety and shelf-life of meat products by inhibiting microbial growth [4]. Nowadays, consumers are more aware of the substances used in food production and are also concerned about the worldwide problem of the multi-drug resistance of microorganisms. This has led to a growing trend to seek natural food additives that can be used for the inhibition of chemical and microbiological spoilage of foods [5]. It has been demonstrated that many plants are effective in microbial growth inhibition in foods [6; 7; 8]. In addition to an antibacterial effect, many plants rich in flavonoids, phenolic and other organic acids have antioxidant, nutritional, and sensory properties in foods [7]. Often, in vitro experiments have been used to study the antioxidant and antibacterial properties of plant materials. Results of in vitro studies are not directly correlated to the effects in different food matrices, because bioactive compounds can be bound to proteins, lipids, or other food ingredients. Moreover, other intrinsic factors can inhibit the antimicrobial effects of bioactive compounds in foods [7; 9]. The use of plant materials containing bioactive compounds such as fruits, vegetables, berries, and their processing by-products is an opportunity to exploit these valuable resources for further use in different food matrices. Furthermore, the use of natural antimicrobials can prevent the negative impact of some synthetic food additives, such as hypersensitivity reactions and intolerance, and achieve the health-promoting effects of plant-derived bioactive compounds on consumers' health [7; 10]. Previous studies [5; 8] have indicated that garden rhubarb petioles (_Rheim japonicum_ L.), blackcurrent berries (_Ribes nigrum_ L.), chokeberries (_Aronia melanocarpa_ Elliott), and tomato (_Solanum lycopersicum_ L.) have antioxidant and antimicrobial properties both in vitro and in producto. Moreover, garlic (_Allium sativum_ L.) and onion (_Allium cepa_ L.), which are both rich in sulphur compounds and phenolic substances, have good antimicrobial properties [11; 12]. Furthermore, allicin in pure form has been found to have antibacterial, antifungal, antiparasitic, and antiviral activity [13]. Garden rhubarb petioles have low total phenolic contents but contain organic acids in large amounts [5]. Blackcurrent berries have high contents of anthocyanins and phenolic acids [14]. Chokeberry berries have high contents of caroten, flavonoids, anthocyanins, and catechines [15]. Tomato is a good source of lycopene, phenolic acids, and flavonoids, and effectively inhibits the growth of yeasts and moulds [8]. Rowanberries (_Sorbus aucuparia_ L.) have high contents of phenolics, flavonoids, and ascorbic acid [16]. [PERSON] et al.