The effect of Ziziphora clinopodioides (0.1 and 0.2%) and nisin (250 and 500 IU/g), both separately and in combination, on mesophilic, psychrotrophic and Enterobacteriaceae microorganisms and also on Staphylococcus aureus and Escherichia coli O157:H7 in raw beef patty during storage at refrigerated temperature for 9 days were evaluated. Carvacrol (64.22%), followed by thymol (19.22%), p‐cymene (4.86%) and γ‐terpinene (4.63%) were the most abundant components of the essential oil. Both the essential oil and nisin significantly (P < 0.05) affected the growth of psychrotrophic, Enterobacteriaceae and mesophilic bacteria and also S. aureus and E. coli O157:H7. Among the experimental groups, samples treated with 0.2% essential oil + 500 IU/g nisin showed the significant most rapid decrease (P < 0.05) in the number of tested microorganisms. Our findings indicate that the essential oil of Z. clinopodioides and nisin has a potential to be applied as an antimicrobial and preservative agent in food products, especially in beef patty.Practical ApplicationsThe genus Ziziphora is widely used as appetitive, carminative, antiseptic, wound‐healing material, sedative, stomach tonic, expectorant and antiseptic in different parts of Iran. In addition, the air‐dried aerial parts of the plant were used in culinary as spice in different foods such as meat and cheese to enhance of their flavor and aroma. In the present study, the essential oil and nisin, both separately and in combination, were very effective in inhibiting Enterobacteriaceae, mesophilic and psychrotrophic microorganisms and also Escherichia coli O157:H7 and Staphylococcus aureus. This essential oil and nisin could be natural antimicrobial alternatives to the synthetic chemical preservatives.
In this study, effect of chitosan (CH) film enriched with cellulose nanoparticle (CN) separately and in combination with ethanolic propolis extract (EPE) on chemical (total volatile base nitrogen content, pH, protein carbonyl content, and peroxide value), microbial (total viable count, psychrotrophic bacteria, Pseudomonas spp., lactic acid bacteria, and Enterobacteriaceae) and sensory (odor, color, and overall acceptability) properties of minced beef meat during refrigerated storage for 14 days was evaluated. Final microbial population decreased approximately 1–5.5 log CFU/g in treated samples compared to control (p < .05). Films containing EPE 2%, EPE 2% + CN 2%, and EPE 2% + CN 1% showed a promising approach for delaying microbial growth as well as lipid and protein oxidation of minced beef meat. There were no negative impacts on sensory properties of samples packed with EPE 2%, EPE 2% + CN 2%, and EPE 2% + CN 1%.
Practical applications
Meat is an important source of essential amino acids, vitamins, minerals, and other nutrients. It is extremely perishable due to high water content, pH, and availability of nutrients. The results of this study showed that minced beef meat's shelf life can be extended by 14 days using chitosan film containing ethanolic propolis extract (1 and 2%) separately and in combination with cellulose nanoparticle (1 and 2%). The synthesized designated films in our study are biodegradable, thus potential in modern active food packaging for the concern of food protection and environmental problems.
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