title: Effect of high intensity ultrasound on the fermentation profile of Lactobacillus sakei in a meat model system.
abstract: The objective of this study was to investigate the efficacy of high intensity ultrasound on the fermentation profile of Lactobacillus sakei in a meat model system. Ultrasound power level (0-68.5 W) and sonication time (0-9 min) at 20 °C were assessed against the growth of L. sakei using a Microplate reader over a period of 24h. The L. sakei growth data showed a good fit with the Gompertz model (R(2)>0.90; SE<0.042). Second order polynomial models demonstrated the effect of ultrasonic power and sonication time on the specific growth rate (SGR, μ, h(-1)) and lag phase (λ, h). A higher SGR and a shorter lag phase were observed at low power (2.99 W for 5 min) compared to control. Conversely, a decrease (p<0.05) in SGR with an increase in lag phase was observed with an increase in ultrasonic power level. Cell-free extracts obtained after 24h fermentation of ultrasound treated samples showed antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella typhimurium at lower concentrations compared to control. No significant difference (p<0.05) among treatments was observed for lactic acid content after a 24h fermentation period. This study showed that both stimulation and retardation of L. sakei is possible, depending on the ultrasonic power and sonication time employed. Hence, fermentation process involving probiotics to develop functional food products can be tailored by selection of ultrasound processing parameters.
authors.affiliation: Teagasc Food Research Centre, Dublin, Ireland; Food Packaging Group, School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Kumari Shikha
authors.initials: KS
authors.lastname: Ojha
authors.affiliation: Food Packaging Group, School of Food and Nutritional Sciences, University College Cork, Cork, Ireland.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Kerry
authors.affiliation: Teagasc Food Research Centre, Dublin, Ireland.
authors.forename: Carlos
authors.initials: C
authors.lastname: Alvarez
authors.affiliation: Teagasc Food Research Centre, Dublin, Ireland.
authors.forename: Des
authors.initials: D
authors.lastname: Walsh
authors.affiliation: Teagasc Food Research Centre, Dublin, Ireland. Electronic address: brijesh.tiwari@teagasc.ie.
authors.forename: Brijesh K
authors.initials: BK
authors.lastname: Tiwari
mesh_terms: D005285:Fermentation; D000070256:Latilactobacillus sakei / Q000378:metabolism*; D008460:Meat; D008962:Models, Theoretical; D014465:Ultrasonics
keywords: Antimicrobial activity; Lactic acid; Meat fermentation; Probiotic; Ultrasonic power