1.Spoilage potential of Vagococcus salmoninarum in preservative-free, MAP-stored brown shrimp and differentiation from Brochothrix thermosphacta on streptomycin thallous acetate actidione agar.
Calliauw F1, Horemans B2, Broekaert K1, Michiels C3, Heyndrickx M1,4. J Appl Microbiol. 2016 May;120(5):1302-12. doi: 10.1111/jam.13107. Epub 2016 Apr 7.
AIMS: During a previous study concerning brown shrimp (Crangon crangon), selective streptomycin thallous acetate actidione (STAA) agar was used to determine the growth of Brochothrix thermosphacta. However, the growth of Vagococcus salmoninarum on this medium was also noticed. This study explores the spoilage potential of this organism when inoculated on sterile shrimp.
2.1-Octanol, a self-inhibitor of spore germination in Penicillium camemberti.
Gillot G1, Decourcelle N2, Dauer G2, Barbier G1, Coton E1, Delmail D3, Mounier J4. Food Microbiol. 2016 Aug;57:1-7. doi: 10.1016/j.fm.2015.12.008. Epub 2015 Dec 30.
Penicillium camemberti is a technologically relevant fungus used to manufacture mold-ripened cheeses. This fungal species produces many volatile organic compounds (VOCs) including ammonia, methyl-ketones, alcohols and esters. Although it is now well known that VOCs can act as signaling molecules, nothing is known about their involvement in P. camemberti lifecycle. In this study, spore germination was shown to be self-regulated by quorum sensing in P. camemberti. This phenomenon, also called "crowding effect", is population-dependent (i.e. observed at high population densities). After determining the volatile nature of the compounds involved in this process, 1-octanol was identified as the main compound produced at high-spore density using GC-MS. Its inhibitory effect was confirmed in vitro and 3 mM 1-octanol totally inhibited spore germination while 100 μM only transiently inhibited spore germination. This is the first time that self-inhibition of spore germination is demonstrated in P.
3.Source, impact and removal of malodour from soiled clothing.
Denawaka CJ1, Fowlis IA1, Dean JR2. J Chromatogr A. 2016 Mar 18;1438:216-25. doi: 10.1016/j.chroma.2016.02.037. Epub 2016 Feb 15.
Static headspace - multi-capillary column - gas chromatography - ion mobility spectrometry (SHS-MCC-GC-IMS) has been applied to the analysis of malodour compounds from soiled clothing (socks and T-shirts), pre- and post washing, at low temperature (20°C). Six volatile compounds (VCs) (i.e. butyric acid, dimethyl disulfide, dimethyl trisulfide, 2-heptanone, 2-nonanone and 2-octanone) were identified. After sensory evaluation of soiled garments they were subjected to laundering with non-perfumed washing powder. The efficiency of the laundering process was evaluated by determining the reduction of each detected volatile compound (VC) post-wash (damp) for socks and T-shirts; VC concentration reductions of between 16 and 100% were noted, irrespective of sample type. Additionally the T-shirt study considered the change in VC concentration post-wash (dry) i.e. after the drying process at ambient temperature. Overall VC concentration reductions of between 25 and 98% were noted for T-shirt samples pre-wash to post-wash (dry).
4.Characterization of beta-cyclodextrin inclusion complexes containing an essential oil component.
Abarca RL1, Rodríguez FJ2, Guarda A2, Galotto MJ2, Bruna JE2. Food Chem. 2016 Apr 1;196:968-75. doi: 10.1016/j.foodchem.2015.10.023. Epub 2015 Oct 8.
An important issue in food technology is that antimicrobial compounds can be used for various applications, such as the development of antimicrobial active packaging materials. Yet most antimicrobial compounds are volatile and require protection. In the present study, the inclusion complexes of 2-nonanone (2-NN) with β-cyclodextrin (β-CD), were prepared by a co-precipitation method. Entrapment efficiency (EE), thermal analysis (DSC and TGA), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), sorption isotherms and antifungal activity were evaluated for the characterization of the inclusion complex (β-CD:2-NN). A higher EE was obtained (34.8%) for the inclusion complex 1:0.5 than for other molar rates. Both DSC and TGA of the inclusion complexes showed the presence of endothermic peaks between 80 °C and 150 °C, attributed to a complexation phenomenon. Antimicrobial tests for mycelial growth reduction under atmospheric conditions proved the fungistatic behaviour of the inclusion complexes against Botrytis cinerea.