Date Published: April 3, 2018
Publisher: Springer Berlin Heidelberg
Author(s): Matthias Schöck, Stefan Liebminger, Gabriele Berg, Tomislav Cernava.
Every year about 20% of the globally produced meat gets lost due to microbial spoilage. Nevertheless, the demand for processed meat is constantly rising and producers are searching for novel strategies to reduce microbial contaminations in their products. In the present study, we evaluated the applicability of alkylpyrazines as antimicrobial agents. These fragrant molecules naturally occur in different vegetables, fruits, roasted nut and meat. Several pyrazine derivatives are readily added to processed products for flavoring purposes in the food industry. To evaluate their potential for application, two derivatives were tested for their antimicrobial activity against meat-associated bacterial contaminants and chicken meat as a whole. Isolates assigned to Carnobacteriaceae, Enterobacteriaceae, Listeriaceae, and Moraxellaceae were substantially inhibited in the pilot tests. Moreover, treatments of pyrazine-susceptible isolates resulted in 4-log reductions in bacterial cell counts. The effect was more pronounced when the model contaminants were exposed to higher concentrations of 5-isobutyl-2,3-dimethylpyrazine. In a first small-scale application with processed chicken meat, it was demonstrated that the antimicrobial effects of 2-isobutyl-3-methylpyrazine can be improved by additionally lowering the water activity on the meat surface when maltodextrin is used as a carrier substance. At low pyrazine dosages, the number of viable bacteria was decreased up to 95% in comparison to the corresponding controls. A complementary imaging method that was developed to assess the efficacy on the product, reinforced the applicability of this two-component system.
Meat is an important energy, protein, and micronutrient source in the human diet. Due to population growth, but also adaption of developing countries, especially China, to the western civilization, the meat demand is steadily increasing (OECD-FAO 2017). The high amount of meat consumption is an enormous burden for the environment nowadays, mainly because it is fastidious in production. It is well known, that animal products generally have a higher water demand than crop products. Depending on the meat source the amount of required water varies from 4300 to 15,400 m3/ton (Mekonnen and Hoekstra 2012). In addition to the enormous demands of natural resources for the production of meat, the preventive use of antibiotics made livestock farms a prevailing source of drug-resistant microorganisms (Heuer et al. 2011). Both, the enormous environmental burden of animal protein and the health implications of intensive farming are alerting. Nevertheless, a considerable proportion of produced meat is wasted nowadays. A recent study of the Food and Agriculture Organization of the United Nations (FAO) showed that almost 20% of the whole meat production is lost annually, this conforms to 263 million tons of meat (FAO 2011). Lipid oxidation, autolytic enzymatic spoilage and microbial spoilage are the main causes for spoilage. They are responsible for the change of color, texture, odor and flavor of meat. Microorganisms are an important cause for such deterioration processes (Zhou et al. 2010). To preserve meat, which provides favorable growth condition for different microorganisms, our ancestors invented different techniques like salting, drying, smoking, fermentation and canning (Dave and Ghaly 2011). All of these traditional techniques extent the shelf life of meat and meat products but underlie the disadvantage that they change composition, appearance, tenderness, flavor, juiciness and nutritive value of the treated meat. Nowadays other techniques like refrigeration, ionizing radiation, chemical preservation, high hydrostatic pressure and packaging are more common (Dave and Ghaly 2011; Zhou et al. 2010). They provide the means for better conservation of the physical and chemical properties of fresh meat. Today’s health awareness of consumers led to new trends in food processing (Bigliardi and Galati 2013). Chemical or artificial substances like nitrites, sulphites or benzoic acid are avoided by many consumers (Dave and Ghaly 2011). Alternative conservation techniques like biopreservation and natural antimicrobials are essential for green label products that attract consumers with their natural image (Zhou et al. 2010). Distinct metabolites from microbial origin, including lactic acid, are known to enhance the shelf life of fresh meat (Stiles 1996). Nevertheless, there is still a great demand for efficient and environmentally friendly strategies.