Food Microbiology Commons^™

Spent Coffee Waste As A Potential Media Component For Xylanase Production And Potential Application In Juice Enrichment, Rajeev Ravindran, Gwilym Williams, Amit Jaiswal

Articles

In this study, spent coffee waste (SCW) was used as the sole carbon source for xylanase production in solid state fermentation mode using Aspergillus niger. A Box–Behnken design was constructed using three parameters viz. temperature, initial moisture content, and log number of sporestodeterminetheoptimalfermentationcondition. Thebestfermentationconditionsforxylanase productionwerefound to beincubation at30◦Cwith aninitial moisture contentof 70%and usingan inoculum of 6.5×106 spores/g of dry SCW. Furthermore, the design of experiments revealed that maintaining a medium composition of 0.2 g of yeast extract, 0.04 g of K2HPO4, and 0.03 g of MgSO4 increased xylanase production. Under optimised solid-state fermentation conditions an enzyme activity of 6495.6 IU/g …

Antimicrobial Effects Of Microwave-Induced Plasma Torch (Minimip) Treatment On Candida Albicans Biofilms, Oliver Handorf, Uta Schnabel, André Bösel, Thomas Weihe, Sander Bekeschus, Alexander C. Graf, Jörg Ehlbeck

Articles

The susceptibility of Candida albicans biofilms to a non-thermal plasma treatment has been investigated in terms of growth, survival and cell viability by a series of in vitro experiments. For different time periods , the C. albicans strain SC5314 was treated with a microwave-induced plasma torch (MiniMIP). The MiniMIP treatment had a strong effect (reduction factor (RF) = 2.97 after 50 s treatment) at a distance of 3 cm between the nozzle and the superior regions of the biofilms. In addition, a viability reduction of 77% after a 20 s plasma treatment and a metabolism reduction of 90% after a …

The Evaluation Of Pathogen Survival In Dry Cured Charcuterie Style Sausages, Jennifer Michelle Mcneil

Theses and Dissertations--Animal and Food Sciences

The objective of this study was to evaluate the survival of non-O157:H7 STEC, Salmonella spp., and S. aureus in dry fermented sausages. Chorizo and Landjager sausages were inoculated with individual bacterial cocktails and stuffed into natural casings. Temperature, relative humidity, pH, and water activity were monitored through fermentation, drying, and storage. Bacterial counts were determined by serial dilution and plated in triplicates on selective media. Plates were incubated at 37°C for 24 hours and colony forming units per gram (CFU/g) were observed.

Results of the first study validate that contaminated raw materials contribute to pathogen survival and background bacteria outcompeted …

Development And Diagnostics Of Novel Non-Thermal Plasmatreatment Systems, Laurence Scally

Doctoral

Non-thermal plasma (NTP) has been a point of interest in many areas over the last few decades. Much research has been,and continues to beundertaken,to understand the fundamentals of plasma discharges. This is such a broad topic due to the very nature and variable dependencies that set the conditions for plasma discharge to occur. This can come in the form of electrode geometry and spacing, dielectric barrier thickness, humidity of environment, material selection for electrodes and dielectric barriers, the power supply used, and the operating gas(es) used. A lot of these influencing factors can be set and kept constant, but still …

Efficacy Of Cold Plasma Functionalised Water For Improving Microbiological Safety Of Fresh Produce And Wash Water Recycling, Apurva Patange, Peng Lu, Daniela Boehm, Patrick J. Cullen, Paula Bourke

Articles

Atmospheric cold plasma (ACP) is an effective method for microbiological decontamination. This study evaluated an alternative water-based decontamination approach for inactivation of bacterial population from fresh produce and in the wash water generated from fresh produce washing. The study characterised ACP inactivation of attached Listeria innocua and Pseudomonas fluorescens inoculated on lettuce in comparison to chlorine treatment. P. fluorescens was sensitive to ACP treatment and was reduced below detection limit within 3 min of treatment. L. innocua population was reduced by ∼2.4 Log10 CFU/g after 5 min of treatment; showing similar inactivation efficacy to chlorine treatment. The microbial load in …

High Voltage Atmospheric Cold Air Plasma Control Of Bacterial Biofilms On Fresh Produce, Apurva Patange, D. Boehm, Dana Ziuzina, Patrick J. Cullen, Brendan Gilmore, Paula Bourke

Articles

Atmospheric cold plasma (ACP) offers great potential for decontamination of food borne pathogens. This study examined the antimicrobial efficacy of ACP against a range of pathogens of concern to fresh produce comparing planktonic cultures, monoculture biofilms (Escherichia coli, Salmonella enterica, Listeria monocytogenes, Pseudomonas fluorescens) and mixed culture biofilms (Listeria monocytogenes and Pseudomonas fluorescens). Biotic and abiotic surfaces commonly occurring in the fresh food industry were investigated. Microorganisms showed varying susceptibility to ACP treatment depending on target and process factors. Bacterial biofilm populations treated with high voltage (80 kV) ACP were reduced significantly (p <  0.05) in both mono- and mixed species biofilms after 60 s of treatment and yielded non-detectable levels after extending treatment time to 120 s. However, an extended time was required to reduce the challenge mixed culture biofilm of L. monocytogenes and P. fluorescens inoculated on lettuce, which was dependent on biofilm formation conditions and substrate. Contained treatment for 120 s reduced L. monocytogenes and P. fluorescens inoculated as mixed cultures on lettuce (p <  0.05) by 2.2 and 4.2 Log10 CFU/ml respectively. When biofilms were grown at 4 °C on lettuce, there was an increased resistance to ACP treatment by comparison with biofilm grown at temperature abuse conditions of 15 °C. Similarly, L. monocytogenes and P. fluorescens exposed to cold stress (4 °C) for 1 h demonstrated increased tolerance to ACP treatment compared to non-stressed cells. These finding demonstrates that bacterial form, mono versus mixed challenges as well as environmental stress conditions play an important role in ACP inactivation efficacy.

Effect Of Cold Plasma On The Techno-Functional Properties Of Animal Protein Food Ingredients, Juan M. Pérez-Andrés, Carlos Álvarez, Patrick J. Cullen, Brijesh K. Tiwari

Articles

Proteins, as food ingredients, are employed in the food industry, not only for their high nutritional value, but also because of their techno-functional properties. Modifications of their native structure due to the action of external factors such as pH, temperature or processing by emerging technologies, can lead to changes in their functionality; and consequently, their applicability. The present study investigates the effects of cold atmospheric air plasma on the techno-functional properties of two common food ingredients (haemoglobin and gelatine from pork), and a novel source of functional proteins extracted from a meat co-product (bovine lung protein). Significant effects were found …