Microbiological Analysis Of Food Research Articles

Bacteriological Contamination Level of Foods and Water Sold With Escherichia Coli, Salmonella spp, Staphylococcus Aureus, Coliforms and Vibrio Cholera in Food Establishments in Nairobi City Kenya

Purpose: Food borne illnesses are major health burden leading to high morbidity and mortality. It is a growing public health concerns worldwide resulting from food and water contaminated by pathogenic microorganism, toxins or chemical hazards. It is estimated that 10 to 20% of food borne illness are contracted from food establishments. The main aim was to determine bacteriological contamination levels of foods and water sold with Escherichia coli, Salmonella spp, Staphylococcus aureus, coliforms and Vibrio cholerae in food establishments in Embakasi South Nairobi City County Kenya.
 Methodology: The study design was descriptive analytical design. The Samples were collected in selected food establishments (Cafeteria, Hotels, Restaurants and food Kiosks) in Embakasi South Sub county Nairobi City County. The study collected 274 samples of food and water randomly sampled and collected using sterile food bags and water bottles within selected establishments and transported to the laboratory in cool boxes packed with ice packs. The samples were analyzed within 6 hours after collection. Microbiological analysis of food and water were borrowed from WHO and bacteriological analytical manual of foods to identify and isolate coliforms, Staphylococcus aureus, Vibrio cholera, Escherichia coli and Salmonella spp.
 Results: It was found that some foods and water sold and consumed in the selected food establishments was contaminated with food borne microorganisms. Escherichia coli isolated in 137 food samples were at 24.1%, Vibrio cholera at 23.4%, Staphylococcus aureus at 32.8%, and Salmonella spp at 4.4%. Total coliforms detected in 137 samples of water were at 43.8% where 32.8% of them were Escherichia coli.
 Unique Contribution to Theory, Practice and Policy: The study concluded there was high level of bacterial contamination of foods and water consumed in selected foods establishments. Nairobi City County health officers should enhance regular sampling of foods and water for microbial quality, health education on sources of food contamination at food eateries and establishments to prevent food and water contamination which later lead to food borne illness outbreak.

Validation according to ISO 16140:2003 of a commercial real-time PCR-based method for detecting Campylobacter jejuni, C. coli, and C. lari in foods

Campylobacteriosis was the most frequently reported zoonosis in the European Union (EU) in 2010, with Campylobacter jejuni, Campylobacter coli, and Campylobacter lari as the most frequently reported species in foodborne outbreaks (FBOs). Relatively sensitive to environmental factors, these species may be present in low numbers. In line with EU policy for food control and FBO detection and in view of the need to reduce response time, we validated an alternative molecular method according to ISO 16140:2003 which establishes the general principle and technical protocol for the validation of alternative methods in the microbiological analysis of food. We used a qualitative real-time PCR commercial kit for the detection of C. jejuni, C. coli, and C. lari in two food categories “fruit and vegetable-based products” and “dairy products”. The validation protocol comprises two phases: the first is a method comparison study of the alternative method against the reference method, and the second is an interlaboratory study of each of the two methods. In the first step, ISO 16140:2003 validation examines the following parameters: limit of detection (LOD); relative accuracy, relative specificity and sensitivity; relative detection level (RDL); and inclusivity and exclusivity. Except for LOD, inclusivity and exclusivity, the other steps were performed against the reference method (ISO 10272:2006).The LOD of the real-time PCR method was set at 4CFU/25g or mL for both food categories. Relative accuracy (98.33%), specificity (96.77%), and sensitivity (100%) were recorded for the food category “fruit and vegetable-based products” and 93.3%, 88.24%, 100%, respectively, for “dairy products”. The RDL according to Fisher's exact test was p=1 for both food categories, for each level, and each food/strain combination. The interlaboratory study results showed correct identification of all 24 blind samples with both methods by all the participating laboratories.The results show that this commercial kit is suitable for the rapid detection of C. jejuni, C. coli, and C. lari on fruit, vegetables and dairy products and may aid in official controls. In conclusion, the use of alternative methods is recommended for the rapid identification of positive samples and the identification of the possible bacterial source in a FBO within 48h.

HACCP implementation in public hospitals: A survey in Crete, Greece

In the island of Crete, Greece, 7 major hospitals offer their services in conjunction with a number of public health centers. Between 2004 and 2009, personnel of the Technological Education Institute (TEI) of Crete, visited these hospitals and carried out food safety surveys. Our basic aim was to evaluate the degree of compliance to food safety and to investigate the actual difficulties that exist during the HACCP implementation process, in hospital mass- catering systems. Evaluation was based on personnel interviewing, checklist screening and microbiological analysis of food and water samples. Two of the hospitals we surveyed were already following HACCP methodology, two had just started to introduce the system and the remaining three were planning HACCP introduction at the time. Some potential problems were detected and unfortunately actual food-safety problems did occur in these hospitals in the same period. The overall results of the above screening have been only partially presented to the moment. Based on the actual findings and experiences of our survey, as well as relevant literature research we emphasize some elements, crucial for implementing and successfully operating HACCP systems in hospitals, as: Managerial commitment; availability and enforcement of risk-informed regulations; hospital registered-dieticians, food technologists, and hygienists involvement; patients menu's planning; hospitals kitchen and food-management personnel training; integration of HACCP procedures with other hospital functions; hygiene supervision by central and regional public health authorities; external food delivery/introduction into the hospital; handling of minimally processed food; regular inspections of kitchenware; food storage conditions; food remaining disposal etc. Last but not least, a crucial element was the absence of HACCP certified suppliers for all food products, especially in the smaller cities.

Microbial contaminants in food: a big issue for a working group of the MoniQA NoE project

Introduction The MoniQA Network of Excellence is an EC funded project working towards the harmonization of analytical methods for monitoring food quality and safety along the food supply chain. This paper summarises both the structure and tasks of the working group on microbial contaminants within the MoniQA NoE and specifically focuses on harmonisation strategies important in the microbiological analysis of food. Objectives There is a need for rapid microbiological methods in order to quickly and efficiently identify harmful pathogens in food sources. However, one of the major problems encountered with many new methods is their market acceptance, as they have to pass extensive validation/ standardisation studies before they can be declared as official standard methods. Methods The working group on microbiological contaminants aims to contribute towards speeding up these prerequisites by collecting information on food law, quality assurance, quality control, sampling, economic impact, measurement uncertainty, validation protocols, official standard methods and alternative methods. Results The present report provides an overview of currently existing methodologies and regulations and addresses issues concerning harmonisation needs. One of the deliverables of the working group is the development of extended fact sheets and reviews based on relevant ‘hot’ topics and methods. The selection of food borne analytes for these fact sheets have been selected based on global, local and individual parameters. The working group has identified 5 groups of stakeholders (governmental bodies, standardisation/validation organisations, test kit/equipment manufacturers, food industry and consumers). Conclusion Current challenges of food microbiology are driven by new analytical methods, changes in the food market and altered consumer desires. The MoniQA NoE is contributing in overcoming these risks and challenges by providing a profound platform on microbiological rapid methods in food analysis to all stakeholders and it is expected that strong interaction within the network and beyond will foster harmonization.

Nutrition and public hygiene among children under five years of age in Mukuru slums of Makadara division, Nairobi

To determine the relationship between sanitation and malnutrition among children below five years. A random sampling followed by an experimental design on microbiological analysis of food and water samples. Mukuru slums of Makadara division in Nairobi City. Eighty food and thirty water samples from households within the study area were used. Poor food and personal hygiene were observed within the households in the study area. Most of the respondents did not practice hygienic methods during food handling such as washing hands and vegetables before preparation. Food especially the leftovers was served at ambient temperatures. Sneezing and coughing over food during preparation were also a common practice which exposed consumers to contamination, Garbage disposal and proper drainage were also poor deepening on the sanitation problem. Microbiological analysis of water and food revealed that food and water quality were poor due to the high coliform counts and confirmed presence of Escherichia coli (E-coli) and Salmonella spp. pathogens which are known causes of diarrhoea in children under five years of age. Poor hygienic and unsanitary practices are major causes of diarrhoea, hence malnutrition in crowded Mukuru slums of Nairobi City.

Food Science Education Publications and Websites

Bird With this issue of the Journal of Food Science Education we inaugurate a new column that will offer brief overviews of current print and nonprint publications that present innovative ways to teach and/or evaluate food science subjects. In each issue we will review up to 10 publications published or updated within the last 2 years. We invite readers to submit print or electronic resources that they would like to share with other readers. Please submit the full text of the article or the URL for the website and an annotation of not more than 100 words. We hope that this column becomes, over time, a clearinghouse for innovative teaching tools and methods. We welcome your comments and resources. Material should be submitted to: Jim Bird, Science & Engineering Center, Fogler Library, Univ. of Maine, Orono, ME 04469 or e-mailed to Jim.Bird@umit.maine.edu. LaBorde LF. (last update 2/24/2006). Food science experiments and learning opportunities for students of all ages. Dept. of Food Science, College of Agricultural Sciences, Penn State Univ. Available at http://www.foodscience.psu.edu/outreach/fun_food_science.html (accessed 5/17/2006) A briefly annotated list of web links to food science experiments and activities for elementary through college students, as well as links for teachers. This site was developed and is maintained by Dr. Luke LaBorde, Dept. of Food Science, Penn State Univ. Lo YM, Fukushima K, Rippen TE, Gdovin SL, and Hahm T-S. 2004. Active assessment for HAACP training: Integrating pedagogical reasoning with primary trait analysis. J Extension 42(6). Available at http://www.joe.org/joe/2004december/iw4.shtml (accessed 5/17/2006) The authors describe an interactive HAACP training program developed at the Univ. of Maryland. The training uses a pedagogical reasoning model and Primary Trait Analysis to design an effective HAACP training program and to access student performance. In this brief paper, the authors present the traits used in designing their problem scenarios as well as the grading criteria used for their ending student interviews. Martindale's The “Virtual” Nutrition Center. Courses, tutorials & databases. Section 1 anatomy to nutrition. Developed and maintained by Jim Martindale. Available at http://www.martindalecenter.com/Nutrition_3_AnNut.html (accessed 5/17/2006) This site, in operation since 1994, offers a wealth of Internet resources for the food science professional. Click on “Food Chemistry Courses” to find online course material from a variety of university food science departments including pdfs of lectures, readings, and charts and diagrams. Continuing down the page, the user will find teaching modules, food chemistry calculations and modeling information, laboratory methods and experiments, microbiological analysis of foods, and sites on flavors, tastes, and smells. Shanley EL, Thompson CA, Leuchner LA, and Zhao Y. 2004. Distance education is as effective as traditional education when teaching food safety. Food Service Technol 4(1):1–8. The authors describe a food safety and sanitation course at the Univ. of Connecticut that was presented in a classroom setting as well as via cd-rom and the Internet. The students were school food service directors who could select the course venue. A fairly detailed table presents the objectives of each of the 8 lessons taught. No significant difference was found in the scores on a nationally recognized food safety examination taken by participants in each group. Information on the distance education course can be found at http://www.team.uconn.edu/foodsafety_course/index.htm. Sigmann SB and Wheeler DE. 2004. The quantitative determination of food dyes in powered drink mixes—a high school of general science experiment. J Chem Ed 81(10):1475–78. Using a centrifuge, an analytical balance, and a spectrophotometer, the authors describe an experiment to analyze the absorbance and percent by mass of 3 food dyes in several Kool-Aid flavored drinks. A table compares the authors' and students' results for percent of mass. The authors note that verification of the results is not possible because dye quantity is proprietary. Supplementary information is available in the online issue of Journal of Chemical Education, for which a paid subscription is required. Sigmann SB and Wheeler DE. 2004. Quantitative determination of citric and ascorbic acid in powered drink mixes—a high school of general science experiment. J Chem Ed 81(10):1479–81. The authors detail their experiment to “… quantitatively determine: first, the amount of total acid; second, the amount of ascorbic acid; and lastly, the amount of citric acid in a given sample of powered drink mix” (p. 1479). As in their experiment to determine food dyes listed above, the authors used Kool-Aid flavored drink mixes. The authors present both their own results and those of the students. The authors note that because this is proprietary information “… percent error for the experimental masses cannot be reported” (p. 1480). Supplementary information is available in the online issue of Journal of Chemical Education, for which a paid subscription is required.

CLOTH‐BASED HYBRIDIZATION ARRAY SYSTEM FOR DETECTION OF TOXIN GENES ASSOCIATED WITH MAJOR FOODBORNE PATHOGENIC BACTERIA

ABSTRACT A simple cloth‐based hybridization array system (CHAS) was developed for the identification of toxin genes associated with major foodborne pathogenic bacteria, including toxigenic Escherichia coli, Vibrio cholerae and Salmonella spp. Bacterial isolates were subjected to a multiplex polymerase chain reaction incorporating digoxigenin (DIG)–deoxyuridine triphosphate and primers targeting a variety of toxin genes (verotoxin, Salmonella enterotoxin, cholera toxin and heat‐labile/stable enterotoxin), followed by hybridization of the amplicons with an array of probes immobilized on polyester cloth and subsequent immunoenzymatic assay of the bound DIG label. This system provided sensitive and specific detection of the different target toxin gene markers in a variety of bacterial isolates, exhibiting the expected patterns of reactivity with a panel of bacteria having defined toxigenicity profiles. The CHAS is a cost‐effective tool facilitating the determination of the potential toxigenic profile of bacteria in the food microbiology laboratory, thus contributing valuable information to the risk‐assessment process in the microbiological analysis of foods.

Rapid Microbiological Methods in Meat and Meat Products

Modern analytical techniques have to provide accurate results in time to permit forward approaches for controlling the microbiological quality of foods. Although the classical microbiological procedures of counting and identification of micro-organisms have been automated, several techniques with quite different principles are now used. The quantification of the microbial load of meat samples can be done in 4–24 hr with methods involving the growth of micro-organisms in liquid media (impedance and turbidimetric methods) and in less than 2 hr with methods counting stained microbial cells or detecting components of microbial cells. Rapid detection of undesirable (pathogens or spoilers) micro-organisms in meat samples can be done with immunological and DNA-based methods. The main techniques which can be used for the microbiological quantification and identification in the meat industries, as well as their applications are reviewed. Possibilities for rapid typing of bacterial isolates are also presented. Finally, some future trends in the microbiological analysis of foods are discussed.

Rapid microbiological methods in meat and meat products

Modern analytical techniques have to provide accurate results in time to permit forward approaches for controlling the microbiological quality of foods. Although the classical microbiological procedures of counting and identification of micro-organisms have been automated, several techniques with quite different principles are now used. The quantification of the microbial load of meat samples can be done in 4–24 hr with methods involving the growth of micro-organisms in liquid media (impedance and turbidimetric methods) and in less than 2 hr with methods counting stained microbial cells or detecting components of microbial cells. Rapid detection of undesirable (pathogens or spoilers) micro-organisms in meat samples can be done with immunological and DNA-based methods. The main techniques which can be used for the microbiological quantification and identification in the meat industries, as well as their applications are reviewed. Possibilities for rapid typing of bacterial isolates are also presented. Finally, some future trends in the microbiological analysis of foods are discussed.

AOAC INTERNATIONAL's three validation programs for methods used in the microbiological analysis of foods

The sheer number of microbiological methods, both rapid and conventional, that have become available during the past ten years has underscored the need for methods validation. The Association of Official Analytical Chemists INTERNATIONAL has responded by offering a variety of validation programs, each with different objectives, approaches, requirements and advantages. The harmonization of these validation efforts with those of other international organizations is needed to achieve uniformity of methods in an expedient and cost-effective manner.

Microbiological analysis of foods in France: standardized methods and validated methods

From a historic situation of total absence of official methods for the microbiological control of foods and the progressive development of the standardization of analysis methods, the French authorities responsible for controlling the hygiene of food products have today entrusted AFNOR with the task of working out analysis methods to be used within the framework of official controls, explicitly making reference, in the statutory texts, to the standardized methods. So-called ‘routine’ standardized methods and commercial methods validated by AFNOR are also used for routine controls. The French system of reference is consistent with the international and European standardized system of reference methods and the MicroVal project will give a European dimension to the certification, by AFNOR, of the commercial methods.

AOAC Overview of Conventional and Rapid Methods for Microbiological Analysis of Foods

AOAC Overview of Conventional and Rapid Methods for Microbiological Analysis of Foods

MICROBIOLOGICAL QUALITY ASSURANCE PROCEDURES IN THE FOOD INDUSTRY

In spite of microbiological Quality Assurance (QA), which has been employed for many years to guarantee the quality of food products in their early stages, food poisoning outbreaks are still increasing. Although food handlers must be educated still further in matters of hygiene, QA (on the microbiological analysis of food) should not be allowed to rest on its laurels, and its present limitations and possible improvements in its specifics and applications are treated here.

An overview of rapid methods in the microbiological analysis of foods

Mise au point bibliographique concernant le controle microbiologique des produits alimentaires tant du point de vue technologique que du point de vue sanitaire

Control of Foaming during Microbiological Analysis of Foods and Recovery of Indicator Organisms

Persistent foam formation occurring during blending of jelly powder (JP), whole egg powder (WEP) and skim milk power (SMP) was demonstrated. Reduction of foaming was uniformly best achieved by using the Colworth Stomacher 400 (STOM) for mixing or blending under a vacuum (VAC). Two hundred, 1000 and 6000 ppm of Dow Corning Antifoam Agent (DAF) was necessary to reduce foaming of JP, SMP and WEP, respectively. Escherichia coli was recovered in similar numbers from JP, SMP and WEP by normal blending (N), STOM, VAC or by the application of 200 ppm of DAF. Significantly lower recovery of Staphylococcus aureus from JP resulted when N or VAC was employed and from SMP when STOM was used. Streptococcus faecalis showed significantly lower recoveries from JP and WEP when STOM or VAC and DAF at 200 ppm were used.