Corry B. Struijk

Detection and enumeration of Listeria monocytogenes in foods

The genus Listeria contains 6 species: L. monocytogenes, L. innocua, L. seeligeri, L. welshimeri, L. ivanovii, and L. grayi (Table 1). L. grayi (29, 34) and L. ivanovii (12, 28) each contain two subspecies, which do not need to be specified in this analysis. A recent taxonomic review of the genus by Rocourt (35) updates the previous reviews (11, 37). L. ivanovii and L. monocytogenesare pathogenic for mice and other animals. However, only L. monocytogenes is commonly associated with human listeriosis. Listeriosis associated infection by L. ivanovii, and even L. seeligeri, is extremely rare in humans. The universal occurrence of L. monocytogenes in food (36) and the risk of contracting food-borne L. monocytogenes listeriosis (41b, http://www.foodsafety.gov/~dms/lmrisk.html) have been thoroughly reviewed recently. This chapter describes the detection and enumeration of L. monocytogenes in foods. Detection of this pathogen in the food processing environment, such as on food contact surfaces and equipment, is described elsewhere (41a).

Microbiological safety assurance applied to smaller catering operations world-wide.: From angst through ardour to assistance and achievement – the facts1

Abstract Providing small food and catering operators, constituting a segment of the small and medium size enterprises (SME), with adequate guidance to ensure microbiologically safe products at the moment of ingestion constitutes a difficult endeavour. It culminates in street vending of foods, particularly in areas with poor sanitary environmental conditions and high ambiental temperatures. The natural occurrence of pathogens on raw materials of animal, and more recently also vegetable origin, is often compounded by an unreliable water supply, poor temperature control and lack of even a rudimentary knowledge of applied food microbiology. The mission statement of the Codex Alimentarius Commission nonetheless includes providing the entire sector of food and catering enterprises world-wide with Codes to enable the plentiful supply of unconditionally safe food. A construct has been devised to gradually but substantially enhance the microbiological safety of products offered by SMEs – in essence complying with the HACCP maxim . Lord Plumb’s extension of Bauman’s HACCP model to longitudinally integrated safety assurance (LISA) has been chosen as the lead policy. Wilson’s Triad, ensuring control of contamination and proliferation throughout the entire food chain provides the essential guidelines. An innovation consists of introducing the concept of attention points , where critical practices or sites cannot yet be brought under control. In this way the mental preparedness to pursue further improvements as required is perennially stimulated. Practical experience is presented of using the ‘Ten Commandments of Safe Catering’ as a tool to focus attention and ensure activity. It was found to be substantially reinforced by introducing autonomous monitoring (‘own checks’) including temperature profile assessment and simple hygiene testing. The latter testing could rely on the use of commercially available Agar Immersion Plating & Contact (AIPC or ‘dip’) slides which constitute a safe tool and one which, owing to its visualization power, strengthens the drive to do better. Cautious use only should be made of the legal SMEs’ obligation, as promulgated in the US and the EU, to comply with HACCP based strategies.

Control of the transmission of Vibrio cholerae and other enteropathogens by foods originating from endemic areas in South America and elsewhere as a model situation

The cholera-pandemic raging in South and Middle America and endemic cholera in other countries call for measures of health protection of the local population, but particularly with respect to the young, old, pregnant and immunocompromised citizens of countries importing food from the areas where the disease has struck. Instead of harshly barring importation, a more humanitarian policy is recommended, relying on assistance of areas presenting risks, with the introduction of and adherence to rigorous measures of longitudinally integrated microbiological safety assurance. This model is equally applicable to other enteric diseases transmitted by food. Examples are given of how canned foods of neutral pH, fishery products, vegetables and certain fruits should be processed for safety. Importation monitoring strategies, linked to this proactive approach to consumer protection, are briefly summarized.

Shaping the new generation of microbiological food safety professionals: Attitudes, education and training

The development of proactive risk management approaches in pursuit of microbiologically safe food is a direct consequence of the ineffectiveness of traditional retrospective strategies. This review catalogues some of the more important observations and insights which have brought about such a change in strategy. By any interpretation the reaction of the scientific community to change has been, in some quarters, as trenchant as it is unwarranted. The anatomy of this opposition and the psychological determinants underpinning it are examined and challenged. The need for an amended perception of the role of monitoring and of microbiological standards in the validation of proactive risk management is explored. Particular attention is given to the importance of accurate analytical methods and to the advantages which derive from the adoption of microbiological reference ranges as opposed to single numerical limits. The need to assess attainable ranges with reference to the intrinsic characteristics of the food u...