Microbial Growth Dynamics in Minced Meat Enriched with Plant Powders

Plant powders with antimicrobial properties can be used in food manufacturing and must comply with the demands of consumers regarding microbiological safety, nutritional value, and sensory properties of foods. The present study aimed to assess the microbial growth inhibitory ability of different plant powders, including by-products of horticultural primary processing (e.g., pomace) in raw and cooked minced pork. The total counts of aerobic mesophilic bacteria, pseudomonads, yeasts, and moulds were studied to assess the microbial growth dynamics in meat samples. Additionally, for the plant powders, which were able to suppress the microbial growth in a total counts dynamics study, the growth potential of Listeria monocytogenes in ready-to-eat (RTE) minced meat samples was estimated by challenge testing. The results showed that the most effective combinations of plant powders in raw minced pork, in relation to the total counts of microorganisms, were 3% apple+1% onion+2% blackcurrant berries (Apple+On+BCber); 3% apple+1% garlic+2% tomato (Apple+Ga+Tom); and 3% apple+2% tomato+1% rhubarb petioles (Apple+Tom+Rhub). However, challenge tests revealed that some plant powders were unable to inhibit the growth of L. monocytogenes. The lowest L. monocytogenes growth potential (δ = 2.74 log cfu/g) was determined for cooked minced pork samples enriched with 2% rhubarb petioles, followed by Apple+On+BCber (δ = 3.63 log cfu/g) and Apple+Tom+Rhub (δ = 3.74 log cfu/g). In minced pork samples without plant additives, the L. monocytogenes growth potential was 7.30 log cfu/g. In conclusion, blends of plant powders may have good potential for developing meat products with acceptable microbiological quality.