List of Titles

125th Anniversary Review: Bacteria in brewing: The good, the bad and the ugly

- Vriesekoop, Frank, Krahl, Moritz, Hucker, Barry, Menz, Garry

Authors: Vriesekoop, Frank , Krahl, Moritz , Hucker, Barry , Menz, Garry
Date: 2013
Type: Text , Journal article
Relation: Journal of the Institute of Brewing Vol. 118, no. 4 (2013), p. 335-345
Full Text: false
Reviewed:
Description: Beer is a beverage that is produced in a multistage process, where some stages of that process are intentionally influenced by microorganisms, while at other stages of the production process microorganisms are actively discouraged. Most of the intentional microbial activity is facilitated by yeast; however bacteria also play an influential role in beer production. This paper will describe the beneficial role of bacteria in the beer production process (the Good), but will also pay due attention to the negative influences bacteria might have on the quality of beer as a commodity (the Bad), and the properties of beer that have given it the status of an inherently safe food for human consumption with regards to disease-causing bacteria (the Ugly). Copyright (C) 2013 The Institute of Brewing & Distilling
Description: C1

Quick View

Changes in the prefermentation static washing regime of Kalamata olives affect the fermentation profile

- Menz, Garry, Bradbury, Mark, Vriesekoop, Frank

Authors: Menz, Garry , Bradbury, Mark , Vriesekoop, Frank
Date: 2008
Type: Text , Journal article
Relation: Food Technology and Biotechnology Vol. 46, no. 3 (Jul-Sep 2008), p. 341-345
Full Text:
Reviewed:
Description: Traditional methods of naturally black olive production employ a series of static washings prior to fermentation. This work investigates the static washings and the effects they have on the subsequent spontaneous fermentation of Kalamata olives. Significant quantities of organic carbonaceous material, including phenolic compounds, were removed during the static washings. The rate of removal peaked after four static washings, and then declined. Bacteria (including lactic acid bacteria) and yeast were found to be present in high numbers throughout the static washings. An increase in the number of static washings resulted in the removal of inhibitory phenolic compounds. This led to a reduction in the lag phase and an increase in the specific growth rate for both the yeast and lactic acid bacteria during the subsequent spontaneous fermentations. However, an increased incidence of spoilage moulds was observed in the fermentations when the olives underwent thirteen static washings.
Description: C1

Dirty Money: An Investigation into the Hygiene Status of Some of the World's Currencies as Obtained from Food Outlets

- Vriesekoop, Frank, Russell, Cryn, Alvarez-Mayorga, Beatriz, Aidoo, Kofi, Yuan, Qipeng, Scannell, Amalia, Beumer, Rijkelt R, Jiang, Xiuping, Barro, Nicolas, Otokunefor, Kome, Smith-Arnold, Cheralee, Heap, Amy, Chen, Jing, Iturriage, Montserat H, Hazeleger, Wilma, DesLandes, Jenny, Kinley, Brandon, Wilson, Kieran, Menz, Garry

Authors: Vriesekoop, Frank , Russell, Cryn , Alvarez-Mayorga, Beatriz , Aidoo, Kofi , Yuan, Qipeng , Scannell, Amalia , Beumer, Rijkelt R , Jiang, Xiuping , Barro, Nicolas , Otokunefor, Kome , Smith-Arnold, Cheralee , Heap, Amy , Chen, Jing , Iturriage, Montserat H , Hazeleger, Wilma , DesLandes, Jenny , Kinley, Brandon , Wilson, Kieran , Menz, Garry
Date: 2010
Type: Text , Journal article
Relation: Foodborne pathogens and disease Vol. 7 , no. 12 (2010), p. 1497-1502
Full Text: false
Reviewed:
Description: A total of 1280 banknotes were obtained from food outlets in 10 different countries (Australia, Burkina Faso, China, Ireland, the Netherlands, New Zealand, Nigeria, Mexico, the United Kingdom, and the United States), and their bacterial content was enumerated. The presence of bacteria on banknotes was found to be influenced by the material of the notes, and there was a strong correlation between the number of bacteria per square centimeter and a series of indicators of economic prosperity of the various countries. The strongest correlation was found with the "index of economic freedom," indicating that the lower the index value, the higher the typical bacterial content on the banknotes in circulation. Other factors that appear to influence the number of bacteria on banknotes were the age of the banknotes and the material used to produce the notes (polymer-based vs. cotton-based). The banknotes were also screened for the presence of a range of pathogens. It was found that pathogens could only be isolated after enrichment and their mere presence does not appear to be alarming. In light of our international findings, it is recommended that current guidelines as they apply in most countries with regard to the concurrent hygienic handling of foods and money should be universally adopted. This includes that, in some instances, the handling of food and money have to be physically separated by employing separate individuals to carry out one task each; whereas in other instances, it could be advantageous to handle food only with a gloved hand and money with the other hand. If neither of these precautions can be effectively implemented, it is highly recommended that food service personnel practice proper hand washing procedures after handling money and before handling food.

Growth and survival of foodborne pathogens in beer

- Menz, Garry, Aldred, Peter, Vriesekoop, Frank

Authors: Menz, Garry , Aldred, Peter , Vriesekoop, Frank
Date: 2011
Type: Text , Journal article
Relation: Journal of Food Protection Vol. 74, no. 10 (2011), p. 1670-1675
Full Text: false
Reviewed:
Description: This work aimed to assess the growth and survival of four foodborne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus) in beer. The effects of ethanol, pH, and storage temperature were investigated for the gram-negative pathogens (E. coli O157:H7 and Salmonella Typhimurium), whereas the presence of hops ensured that the gram-positive pathogens (L. monocytogenes and S. aureus) were rapidly inactivated in alcohol-free beer. The pathogens E. coli O157:H7 and Salmonella Typhimurium could not grow in the mid-strength or full-strength beers, although they could survive for more than 30 days in the mid-strength beer when held at 4Â°C. These pathogens grew rapidly in the alcoholfree beer; however, growth was prevented when the pH of the alcohol-free beer was lowered from the "as received" value of 4.3 to 4.0. Pathogen survival in all beers was prolonged at lowered storage temperatures. Copyright Â© International Association for Food Protection.

Isolation, identification, and characterisation of beer-spoilage lactic acid bacteria from microbrewed beer from Victoria, Australia

- Menz, Garry, Andrighetto, Christian, Lombardi, Angiolella, Corich, Viviana, Aldred, Peter, Vriesekoop, Frank

Authors: Menz, Garry , Andrighetto, Christian , Lombardi, Angiolella , Corich, Viviana , Aldred, Peter , Vriesekoop, Frank
Date: 2010
Type: Text , Journal article
Relation: Journal of the Institute of Brewing Vol. 116, no. 1 (2010), p. 14-22
Full Text: false
Reviewed:
Description: Lactic acid bacteria are the most frequently encountered beer-spoilage bacteria, and they may render beer undrinkable due to the production of lactic acid, diacetyl, and turbidity. Micro-brewed beer is typically sold unpasteurised, leaving it more susceptible to spoilage by lactic acid bacteria. In this study, the incidence of lactic acid bacteria in bottled microbrewed beer from Victoria, Australia was investigated. A total of 80 beers from 19 breweries were screened for lactic acid bacteria. Almost 30% contained culturable lactic acid bacteria, and many had lactic acid levels well above the flavour threshold. Ethanol, hops, and the pH levels of the beers were not predictors for spoilage in the beers examined, and contamination appeared to be more closely linked to the source brewery. The 45 lactic acid strains isolated from these beers were identified by RAPD-PCR, with Lactobacillus brevis being the most frequently isolated species. All isolates were capable of spoiling beer and contained putative hop resistance genes. At typical beer levels, pH and ethanol had no effect on the growth of the particular spoilage bacteria isolated in this study. Â© 2010 The Institute of Brewing & Distilling.
Description: 2003008145

Physical and chemical changes during the maturation of Gordal Sevillana olives (Olea europaea L., cv. Gordal Sevillana)

- Menz, Garry, Vriesekoop, Frank

Authors: Menz, Garry , Vriesekoop, Frank
Date: 2010
Type: Text , Journal article
Relation: Journal of Agricultural and Food Chemistry Vol. 58, no. 8 (2010), p. 4934-4938
Full Text: false
Reviewed:
Description: A series of physical and chemical changes occur as olives mature on the tree, and these changes are important for the production of oil and table olives. The aim of this study was to increase the understanding of the maturation process of Gordal Sevillana olives, to optimize harvest timing, and to determine the most appropriate harvesting and post-harvesting processing methods. During maturation, the olive size, flesh/pit ratio, and oil content increased, with a maximum oil content of 72 g kg(-1) (wet weight). Changes in the fatty acid composition are reported. Levels of both total sugars and total phenolic compounds slightly decreased over the maturation period; however, we observed that these compounds were continually being synthesized until full black maturity. The optimal harvest time for the production of Gordal Sevillana as Spanish-style green olives occurred immediately prior to the color change from green to turning color, at which point the sugar levels and flesh/p! it ratio were at maximum levels.

The growth and survival of food-borne pathogens in sweet and fermenting brewers' wort

- Menz, Garry, Vriesekoop, Frank, Zarei, Mehdi, Zhu, Bofei, Aldred, Peter

Authors: Menz, Garry , Vriesekoop, Frank , Zarei, Mehdi , Zhu, Bofei , Aldred, Peter
Date: 2010
Type: Text , Journal article
Relation: International Journal of Food Microbiology Vol. 140, no. 1 (2010), p. 19-25
Full Text: false
Reviewed:
Description: The aim of this study was to investigate the factors affecting the survival and growth of four food-borne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus) in sweet and fermenting brewery wort. The Gram-negative pathogens (E. coli and Salm. Typhimurium) were capable of growth during the initial stages of fermentation in hopped wort, although they were quickly inactivated when added during the later stages of fermentation. When the wort was left unpitched, the two Gram-negative pathogens grew unabated. Pathogen growth and survival was enhanced as the pH was increased, and as both the ethanol and original gravity were decreased. Although having no effect on the Gram-negative pathogens, low levels of hop iso-
Description: 2003008146

Showing items 1 - 8 of 8