A review of analytical, separation, concentration and segregation techniques in microbiology

There are several major factors responsible for accentuating the need for r eal-time defection techniques for foodborne pathogens. These include: (1) t he general upward trends in the reported statistics of food-poisoning world wide and emergence of foodborne diseases (e.g Salmonella enteritidis, Campy lobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes and Yersi nia enterocolitica); (2) the strict national and international food safety and hygiene regulations, including the US Pathogen reduction Act (e.g setti ng zero tolerance classification by the USDA FSIS of E. coli O157:H7) and i mplementation of mandatory standards for microorganisms in the recent EEC d irectives for shell-fish, dairy products and eggs; (3) and the progressive introduction of a range of quality assurance and quality management program s (such as BS 5750, ISO 9000 and TQM) to enhance the efficiency and streaml ine modern food production and distribution systems. Increasing adoption of the HACCP approach to food production together with the recent information derived from a range of mathematical models for pred iction of growth and survival of food-poisoning microorganisms can effectiv ely reduce the potential risks by microbial contamination. Microbiological testing should be considered in the context of properly evaluated and imple mented safety assurance systems. The role of microbiological resting in rel ation to HACCP has been discussed and considered in detail elsewhere (Hall 1994). Over the past ten years, a plethora of new methods for the microbiological examination of food has become available. The performance of these methods, outside of the originating laboratory, has to be effective and reliable, a nd this can only be assessed by proper validation of the methods. Validated methods are used by food control laboratories to analyze commodities to ve rify regulatory compliance. There are several international schemes availab le for validation of modern microbiological methods, including AOAC Interna tional, IDF procedures, EMMAS and Microval (Anon. 1996). In order to produc e consistently reliable data, a laboratory must ensure appropriate quality assurance measures are in place. These include fully documented methods, pr oper trained laboratory staff and participation in a proficiency testing sc heme, many of which are currently available.