François Bourdichon - Articles and news items
Barry Callebaut’s François Bourdichon looks at Listeria monocytogenes and what we’ve learned from the last 30 years, while Lilia M. Santiago-Connolly and Raghu Ramaswamy from Heinz look at the need for risk assessment and validation in frozen food manufacturing…
Issue 5 2013 • 4 November 2013 • François Bourdichon, Corporate Food Safety, Microbiology and Hygiene Manager, Barry Callebaut
Taxonomy and classification of microorganisms are based on criteria that do not always, if ever, fit with the complexity of the microbial world. Commensal, starter, probiotic, pathogen? Since the early days of Pasteur and Koch, this approach is not anymore applicable for most of the major foodborne and/or waterborne microorganisms. In the past few years, due to the evolution of regulation and need for safety demonstration, microbiologists face the new challenge of understanding and demonstrating the mechanism of action (most commonly pleiotropic) of one organism in order to assess its potential application. Among the most debated genera, one might like to see how those consequences apply to the benefit / risk assessment of Enterococcus spp., formerly Streptococcus spp. Lancefield Group D or faecal Streptococci (for microbes also, sometimes the name does not help).
Issue 5 2012 • 6 November 2012 • François Bourdichon, Nestlé Research Centre; Joerg Seifert, International Dairy Federation and Egon Bech Hansen, Technical University of Denmark
Fermentation as a chemical process was initially described in the mid-19th century by Louis Pasteur as ‘a vie sans l’air’, the metabolic process of deriving energy from organic compounds without the involvement of an exogenous oxidising agent. Fermentation, as a process for manufacturing fermented foods, is today used more broadly than the historical definition of fermentation. Fermented foods have been subjected to the action of microorganisms during which desirable biochemical changes occur, causing significant modification to the food matrix2,13.
Fermented foods are typically associated with local and traditional food consumption. The growing body of evidence with regard to microorganisms and their ecological role in the food matrix has led to industrial application of the process of fermentation starting in the early 20th century through use of specific dedicated microbiota with various levels of characterisation.
In recent decades, the use of microbial food cultures (MFC) has come under various regulatory frameworks in many countries, directly or indirectly. Several of these regulatory frameworks put emphasis on ‘the history of use’, ‘traditional food’, or ‘general recognition of safety’ without clear guidelines for the expected level of evidence.
Issue 3 2012 • 3 July 2012 • François Bourdichon and Katia Rouzeau, Food Safety Microbiology, Quality and Safety Department, Nestlé Research Centre
‘Something is fishy’ is a widely used expression over a doubtful, suspicious situation, a good example of how mankind has taken advantage of microbial spoilage to assess the wholesomeness of a food product. The reduction of trimethylamine oxide to trimethylamine by bacteria associated primarily with the marine environment (e.g. Alteromonas and Vibrio) and animal intestines (Enterobacteriaceae) constitutes this major spoilage reaction during the storage of marine fish and typically identified ‘fishy’ as off note. The microbial alteration of fish can be therefore organoleptically identified by consumers, considering the food as suspicious for consumption1.
Spoilage of food involves any change which renders food unacceptable for human consumption and may result from a variety of causes, which include: Insect damage; Physical injury due to freezing, drying, burning, pressure, radiation; Activity of indigenous enzymes in plant and animal tissues; Chemical changes not induced by microbial or naturally occurring enzymes (These changes usually involve O2 and light and other than microbial spoilage are the most common cause of spoilage e.g. oxidative rancidity of fats and oils and the discolouration of cured meats); and growth and activity of microorganisms: bacteria, yeasts and moulds.
Issue 5 2010 • 5 November 2010 • François Bourdichon & Mohamed Hedi Ben Cheikh, Food Safety Centre, Danone Corporate
Mathematics is everywhere. One might go into the field of biology to avoid numbers and equations, yet they are still there, helping food technologists to decipher the behaviour of micro-organisms in different food matrices and along the process chain. Since the negation of the spontaneous generation theory by Louis Pasteur in the 19th Century, the different phases of bacterial growth have been well defined: lag phase, exponential phase, stationary phase. Yet this simplistic approach of molecular mechanism isn’t that easy to model through polynomial equation, when taking into consideration the food matrix and role of preservative factors.
Issue 2 2010 • 12 May 2010 • François Bourdichon, Food Safety Centre, Danone Corporate
Probiotics are used to bring health benefits to consumers through foods and are defined as “live micro-organisms which, when administered in adequate amounts, confer a health benefit on the host[Ref 18].” Commercialised all around the world since the early 1920’s, mostly focused on Bifidobacterium and Lactobacillus genera, in the last fifteen years there has been a rising awareness reported in scientific literature on putative adverse events caused by strains belonging to this genera, if not adverse events supposedly caused by probiotic prophylaxis, e.g. the recent Dutch probiotic prophylaxis study on severe acute pancreatitis[Ref 6]. Saccharomyces boulardii is the sole probiotic yeast strain widely used nowadays, isolated from the fruit of litchi and mangosteen in Indochina in 1923. Marketed and evaluated as a drug, its use differs from other probiotic strains, considered as part of the food diet, with different efficacy and safety evaluation[Refs 20,25,45].
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