Postprocessing microflora of commercial attieke (a fermented cassava product) produced in the south of Côte d'Ivoire

The distribution and presence of hygiene indicator and pathogenic micro‐organisms in 375 samples of attieke marketed in Côte d'Ivoire, and their roles in the food poisoning were evaluated. Microbiological analyses were carried out, which included the total viable bacteria, coliforms, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus spores, fungi and Clostridium perfringens. The results revealed that the viable bacteria counts ranged from 2·2 ± 1·2 × 10⁵ to 3·4 ± 1·4 × 10⁶ CFU g^?1, while the yeasts and the moulds counts ranged, respectively, from 2·4 ± 0·12 × 10⁴ to 9·8 ± 0·4 × 10⁵ CFU g^?1 and 1·3 ± 0·7 × 10¹ to 1·7 ± 0·7 × 10² CFU g^?1. Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Citrobacter freundi, Enterobacter amnigenus, Citrobacter youngae, Enterobacter aerogenes, Klebsiella pneumoniae, Serratia marcescens, Enterobacter agglomerans and Klebsiella oxytoca were the bacteria isolated, and Rhizopus spp., Mucor spp., Thamnidium spp., Fusarium spp., Moniliella spp. the fungi. Escherichia coli, Clostridium perfringens and Salmonella spp. were not found. The occurrence of some bacteria and fungi illustrate that attieke collected in Côte d'Ivoire markets may act as a reservoir of pathogenic micro‐organisms for human.

Significance and Impact of Study

This study demonstrates the great need to carry out microbiological tests frequently on attieke and even more the need to apply correct HACCP system during the production. Attieke is especially a well‐known product in West Africa; hence, it is extremely important to ensure an adequate microbiological quality to guarantee consumers health. Overall, the study highlighted the need for effective communication on microbiological food risks, proper instruction and supervision in food‐handling procedures, greater education on food safety risks.     

The evaluation of the microbial safety of fresh ready‐to‐eat vegetables produced by different technologies in Italy

Aims: The study was performed to evaluate the safety of whole and RTE vegetables and to investigate the effectiveness of different preventive strategies for the quality assurance of RTE vegetables collected from three Italian production systems. Producer 1, applied a strict system in compliance with GAP‐ GMP – HACCP, Producer 2 used chlorine disinfection at a second washing step, and Producer 3 using a physical microbial stabilization. Methods: During the period 2005–2007, a total of 964 samples including whole vegetables and RTE salads, collected from three different producers in central Italy, were analysed to quantify the aerobic mesophilic count (AMC) and Escherichia coli, and for the presence of Salmonella spp, Listeria monocytogenes, E. coli O157:H7, hepatitis A virus and Norovirus (NoV). Results: None of the whole vegetable samples were positive for L. monocytogenes, E. coli O157:H7, HAV and NoV; however, a low prevalence of Salmonella was found. No pathogens were detected with cultural methods in any of the RTE vegetables analysed, only two RTE samples were positive for L. monocytogenes with PCR, but were not confirmed by the cultural method. The median values of AMC in RTE vegetables measured 24 h after packaging were statistically different among the 3 producers (5·4 × 10⁶, 1·5 × 10⁷ and 3·7 × 10⁷ CFU g^?1, respectively; P = 0·011). The lowest level was detected in Producer 1. Conclusion: The products that were processed applying rigorously GAP, GMP and HACCP showed a better microbiological quality than those processed with chemical or physical stabilization. Study Significance and Impact: The results of the study evidenced the efficacy of GAP, GMP and HACCP in improving microbiological quality of whole and RTE vegetables.     

Antibacterial activity of different degree of hydrolysis of palm kernel expeller peptides against spore-forming and non-spore-forming bacteria

Aims: The goal of this study was to determine inhibitory effect of palm kernel expeller (PKE) peptides of different degree of hydrolysis (DH %) against spore‐forming bacteria Bacillus cereus, Bacillus circulans, Bacillus coagulans, Bacillus licheniformis, Bacillus megaterium, Bacillus pumilus, Bacillus stearothermophillus, Bacillus subtilis, Bacillus thuringiensis, Clostridium perfringens; and non‐spore‐forming bacteria Escherichia coli, Lisinibacillus sphaericus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium and Staphylococcus aureus. Methods and Results: A range of DH % (50–100) of PKE peptides was prepared using alcalase, and hydrolysis conditions were determined using response surface methodology (RSM). The influence of pH (6·5–10·5), temperature (35–65°C), enzyme/substrate ratio (1–5%) and substrate concentration (1–2%) were studied on the response of the DH. The antibacterial activity of different DH % of PKE peptides was tested by using disc diffusion assay and micro‐broth dilution assay. According to the minimum inhibitory concentration (MIC) test on each of the PKE peptides of different DH %, the 70 DH % PKE peptide showed greater inhibitory effect compared to the 100 DH % PKE peptide against B. cereus, B. coagulans, B. megaterium, B. pumilus, B. stearothermophillus, B. subtilis, B. thuringiensis, Cl. perfringens, Lisinibacillus sphaericus and L. monocytogenes. Conclusions: The 70 DH % PKE peptides exhibited greatest overall antibacterial effect of the various peptides of PKE evaluated. Further research is needed to determine the mode of action of PKE peptides. Significance and Impact of the Study: Palm kernel expeller peptides, a natural plant product, effectively inhibited the growth of spore‐forming and non‐spore‐forming Gram‐positive bacteria. Potentially, PKE peptides could be used in food preservation and developed as antibacterial agent in the pharmaceutical industry.     

Occurrence of microorganisms of public health and spoilage significance in fruit juices sold in retail markets in Greece

Fruit juices are an important part of the modern diet in many countries. However, few data are available concerning the microbiological quality of the fruit juices sold in Greece. Using standard microbiological procedures, we conducted a bacteriological survey of commercially sold, pasteurized, shelf-stable fruit juices from retail markets. A total of 120 samples of fruit juices sold in various retail markets were examined for their bacteriological quality. The pH of the tested juices was 2.4–4.8. Bacteria were isolated from 51 samples (42.5%) and fungi from 78 samples (65%). Escherichia coli O157:H7 was detected in four of the analyzed samples (3.34%), and Staphylococcus aureus was detected in four different samples (3.34%). In 11 samples (9.1%), the total number of microorganisms detected was as high as 125 colony-forming units (CFU). Acidophilic microorganisms were isolated from 26 samples (21.7%) and Blastomyces was detected in 46 samples (38.3%). All samples were negative for Lactobacillus, Clostridium perfrigens, Salmonella spp., Bacillus cereus, total coliforms, E. coli, and Listeria monocytogenes.Many of the microorganisms detected may cause disease in humans; thus, a number of the tested samples did not meet the Greek guidelines for the microbiological quality of juices. Use of a Hazard Analysis Critical Control Point (HACCP) system should be generally introduced into the juice industry sector to improve the quality of fruit juices, as well as other manufactured foods.     

Microbiological Analysis of Stuffed Mussels Sold in the Streets

Stuffed mussel is a traditional food that sold by street venders in various countries. In the present study, samples of stuffed mussels were collected from various places in Ankara. The mussels were analyzed to show the microbiological risks for human health. Thirty samples (600 stuffed mussels in total) were collected periodically and microbiological analyses were performed by standard procedures for Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella sp., Clostridium sp. In terms of Salmonella sp., approximately 50% of samples were not suitable for consumption. Besides, in accordance with Turkish Food Codex Microbiological Criteria Announcement in terms of E. coli 30%, in terms of B. cereus 80%, in terms of S. aureus 76.6%, in terms of Clostridium perfringens 13.3% of these samples were not suitable for consumption. The aim of this study is to discuss the microbiological quality of stuffed mussels as a ready-to-eat food according to Turkish Food Codex (TFC). The result of this investigation indicates that stuffed mussels as a street food may constitute a potential health hazard, depending on contamination level and lack of sanitary practices, and therefore, handling practices should require more attention and improvement.     

Prior frozen storage enhances the effect of edible coatings against Listeria monocytogenes on cold-smoked salmon during subsequent refrigerated storage

Aims: Listeria monocytogenes is a major safety concern for ready‐to‐eat foods. The overall objective of this study was to investigate whether prior frozen storage could enhance the efficacy of edible coatings against L. monocytogenes on cold‐smoked salmon during subsequent refrigerated storage. Methods and Results: A formulation consisting of sodium lactate (SL, 1·2–2·4%) and sodium diacetate (SD, 0·125–0·25%) or 2·5% Opti.Form (a commercial formulation of SL and SD) was incorporated into each of five edible coatings: alginate, κ‐carrageenan, pectin, gelatin and starch. The coatings were applied onto the surface of cold‐smoked salmon slices inoculated with L. monocytogenes at a level of 500 CFU cm^?2. In the first phase, the slices were first frozen at ?18°C for 6 days and stored at 22°C for 6 days. Alginate, gelatin and starch appeared to be the most effective carriers. In the second phase, cold‐smoked salmon slices were inoculated with L. monocytogenes, coated with alginate, gelatin or starch with or without the antimicrobials and stored frozen at ?18°C for 12 months. Every 2 months, samples were removed from the freezer and kept at 4°C for 30 days. Prior frozen storage at ?18°C substantially enhanced the antilisterial efficacy of the edible coatings with or without antimicrobials during the subsequent refrigerated storage. Conclusions: Plain coatings with ≥2 months frozen storage and antimicrobial edible coatings represent an effective intervention to inhibit the growth of L. monocytogenes on cold‐smoked salmon. Significance and Impact of the Study: This study demonstrates the effectiveness of the conjunct application of frozen storage and edible coatings to control the growth of L. monocytogenes to enhance the microbiological safety of cold‐smoked salmon.     

Frequency of indicator bacteria,Salmonella and diarrhoeagenic Escherichia coli pathotypes on ready‐to‐eat cooked vegetable salads from Mexican restaurants

The presence of coliform bacteria, faecal coliforms, Escherichia coli, diarrhoeagenic E. coli pathotypes (DEP) and Salmonella were determined in ready‐to‐eat cooked vegetable salads (RECS) from restaurants in Pachuca city, Mexico. The RECS were purchased from three types of restaurants: national chain restaurants (A), local restaurants (B) and small restaurants (C). Two restaurants for each A and B, and three for C, were included. Forty RECS samples were purchased at each A and B restaurant and 20 at each C restaurant. Of the overall total of 220 analysed samples, 100, 98·2, 72·3, 4·1 and 4·1% had coliform bacteria, faecal coliforms, E. coli, DEP and Salmonella, respectively. Identified DEP included enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC) and Shiga toxin‐producing E. coli (STEC). The EPEC, ETEC and STEC were isolated each from 1·4% of samples. No E. coli O157:H7 were detected in any STEC‐positive samples. The analysis of Kruskal–Wallis anova and median test of microbiological data showed that the microbiological quality of RECS did not differ between the different restaurants (P > 0·05).

Significance and Impact of the Study

This is the first report regarding microbiological quality and Salmonella, enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC) and Shiga toxin‐producing E. coli (STEC) isolation from ready‐to‐eat cooked vegetable salads from Mexican restaurants. Ready‐to‐eat cooked vegetable salads could be an important factor contributing to the endemicity of EPEC, ETEC and STEC, and Salmonella caused gastroenteritis in Mexico.     

Yeasts and moulds contaminants of food ice cubes and their survival in different drinks

Aims

To evaluate the levels of unicellular and filamentous fungi in ice cubes produced at different levels and to determine their survival in alcoholic beverages and soft drinks.

Methods and Results

Sixty samples of ice cubes collected from home level (HL) productions, bars and pubs (BP) and industrial manufacturing plants (MP) were investigated for the presence and cell density of yeasts and moulds. Moulds were detected in almost all samples, while yeasts developed from the majority of HL and MP samples. Representative colonies of microfungi were subjected to phenotypic and genotypic characterization. The identification was carried out by restriction fragment length polymorphism (RFLP) analysis of the region spanning the internal transcribed spacers (ITS1 and ITS2) and the 5·8S rRNA gene. The process of yeast identification was concluded by sequencing the D1/D2 region of the 26S rRNA gene. The fungal biodiversity associated with food ice was represented by nine yeast and nine mould species. Strains belonging to Candida parapsilosis and Cryptococcus curvatus, both opportunistic human pathogens, and Penicillium glabrum, an ubiquitous mould in the ice samples analysed, were selected to evaluate the effectiveness of the ice cubes to transfer pathogenic microfungi to consumers, after addition to alcoholic beverages and soft drinks. All strains retained their viability.

Conclusions

The survival test indicated that the most common mode of consumption of ice cubes, through its direct addition to drinks and beverages, did not reduce the viability of microfungi.

Significance and Impact of the Study

This study evidenced the presence of microfungi in food ice and ascertained their survival in soft drinks and alcoholic beverages.     

PCR-DGGE analysis of bacterial community dynamics in kava beverages during refrigeration

Aims: Kava beverages are highly perishable even under refrigerated conditions. This study aimed to investigate the bacterial community dynamics in kava beverages during refrigeration. Methods and Results: Four freshly made kava beverages were obtained from kava bars and stored at 4°C. On days 0, 3 and 6, the aerobic plate count (APC), lactic acid bacteria (LAB) count and yeast and mould count (YMC) of the samples were determined. Meanwhile, bacterial DNA was extracted from each sample and subjected to the polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE). Moreover, species‐specific PCR assays were employed to identify predominant Pseudomonas spp. involved in kava spoilage. Over the storage period, the APC, LAB count and YMC of the four kava beverages all increased, whereas their pH values decreased. The DGGE profile revealed diverse bacterial populations in the samples. LAB, such as Weissella soli, Lactobacillus spp. and Lactococcus lactis, were found in the kava beverages. Species‐specific PCR assays detected Pseudomonas putida and Pseudomonas fluorescens in the samples; Ps. fluorescens became dominant during refrigeration. Conclusions: LAB and Pseudomonas may play a significant role in the spoilage of kava beverages. Significance and Impact of the Study: This study provides important information that may be used to extend the shelf life of kava beverages.     

Microbial challenges of poultry meat production

Food safety and shelf-life are both important microbial concerns in relation to broiler meat production. Focus is mainly placed on the absence or control of potentially pathogenic microbes such as Salmonella spp. and Campylobacter spp. but, from the commercial point of view, other spoilage bacteria also play a role as potential threats. Regarding food safety, the primary target should be the production of pathogen-free live animals, thus allowing slaughter plants to keep the processing line free of those microorganisms.Consumers believe that quality of foods from organic production is superior to foods from conventional production. The aim of the present study was to evaluate and compare the bacterial quality of chicken meat from organic and conventional production on the basis of traditional meat quality criteria. Fresh free grazing broiler carcasses were purchased directly from rural households (n = 80) and fresh retail chicken parts from conventional broiler carcasses from the local supermarkets in the region of Epirus (Poultry Producers Association. Arta) (n = 200).The samples were microbiologically tested for the presence of bacteria such as: Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Enterobacteriaceae, Escherichia coli, Campylobacter spp., and C. perfringens. Total count of aerobic mesophilic bacteria was also determined. Bacteriological tests were performed by means of standard methods of isolation and identification of individual species of bacteria according to ISO requirements. API-tests (bioMerieux) and Vitek 2 Identification System (bioMerieux) were used for biochemical determination. High levels of microbial contamination and occurrence of pathogenic bacteria at then fresh free grazing broiler carcasses reflect the poor hygienic quality of the slaughter conditions in the rural households.     

Development and validation of stable reference materials for food microbiology using Bacillus cereus and Clostridium perfringens spores

Aims: To develop a new type of microbiological Reference Materials (RMs), displaying long‐term stability at room temperature. The purpose was to produce and validate two batches of RMs for the enumeration of Bacillus cereus and Clostridium perfringens. Methods and Results: The RMs were based on spores of B. cereus and Cl. perfringens, adsorbed on calcium carbonate pellets. Two batches of 1000 units were manufactured and validated in compliance with ISO guide 35. After verification of their homogeneity, the stability of the ‘RM‐B. cereus’ and ‘RM‐Cl. perfringens’ batches was proven during at least 36 and 9 months, respectively, at room temperature. The validation study was completed by international collaborative trial involving 12 laboratories, allowing the validation of the assigned values. Conclusions: The methodology developed in this work enabled to produce easy‐to‐handle and cost‐effective RMs, displaying an unprecedented stability at room temperature, a good homogeneity and a precise and validated assigned value. Significance and Impact of the Study: This study revealed new paths for the development of stable microbiological RMs. Overcoming the intrinsic instability of the living cells makes it possible to produce valuable tools for the quality assurance of microbiology laboratories.     

Behaviour of Listeria monocytogenes in packaged water buffalo mozzarella cheese

Aims: The aim of the study was to evaluate the behaviour of Listeria monocytogenes in the conditioning liquid of packaged water buffalo mozzarella cheese (WBMC). Methods and Results: The conditioning liquid was contaminated with L. monocytogenes, and the contaminated samples were stored at four different storage temperatures: 5 and 10°C for 22 days; 20°C for 9 days; 20°C for 3 days and then at 5°C for 6 days. The results showed that L. monocytogenes concentration decreased when contaminated samples were stored at 5°C. When WBMC was stored at 20°C and at 10°C, L. monocytogenes started to grow after a lag phase of 3 and 10 days, respectively. When samples were stored at variable temperature conditions, L. monocytogenes numbers showed a lag phase of 5 days. Conclusions: Use of a conditioning liquid characterized by acidity and a correct storage temperature is able to counteract pathogen replication during shelf life. A high concentration of lactic acid bacteria was associated with effective control of L. monocytogenes but the role of lactic acid bacteria in WBMC conditioning liquid requires further investigation. Significance and Impact of the Study: According to European regulations, food producers should be able to justify decision‐making on the shelf life assigned to their products, taking into account reasonable storage conditions and use by consumers. The results of the trial yielded information for producers of WBMC and similar cheeses for decision‐making on product shelf life.     

Rapid detection of Vibrio parahaemolyticus by PCR targeted to the histone-like nucleoid structure (H-NS) gene and its genetic characterization

Aims: The aim of this study was to explore a new PCR target gene for Vibrio parahaemolyticus, based on the histone‐like nucleoid structure (H‐NS) gene. Methods and Results: Primers for the H‐NS gene were designed for specificity to V. parahaemolyticus and incorporated into a PCR assay. The PCR assay was able to specifically detect all of the 82 V. parahaemolyticus strains tested, but did not result in amplification in the 47 other Vibrio spp. and nonVibrio spp. strains. The detection limit of the PCR assay was 0·14 pg purified genomic DNA and 1·8 × 10⁵ CFU g^?1 spiked oyster samples from V. parahaemolyticus RIMD2210633. Furthermore, a multiplex PCR assay targeting the hns, tdh and trh genes was successfully developed to detect virulent V. parahaemolyticus strains. Conclusions: The H‐NS‐based PCR assay developed in this study was sensitive and specific, with great potential for field detection of V. parahaemolyticus in seawater or seafood samples. Significance and Impact of the Study: The H‐NS gene was validated as a new specific marker gene in PCR assays for accurate detection and identification of V. parahaemolyticus, which has the potential to be applied in diagnostics and taxonomic studies.     

Case report of clinical salmonellosis by Salmonella Typhimurium that occurred in Portuguese children

Aims: Aim of this study is to characterize clinical isolates of Salmonella Typhimurium that occurred in Portuguese children on the basis of their virulence and antimicrobial resistance profiles and pulsed‐field gel electrophoresis typing and to analyse possible strain relatedness. Methods and Results: Different Salmonella serotypes were isolated from clinical cases of salmonellosis that had occurred in two Portuguese hospitals (a total of 259 isolates). All Salm. Typhimurium strains, with the age of the patients known, (total of 26 isolates) were selected for this study. These isolates were characterized for their virulence gene profiles (agfA, iroB, slyA, hin/H2, spv), antimicrobial resistance profiles and investigated for the occurrence of multidrug‐resistant Salm. Typhimurium DT 104 by PCR. Salmonella isolates showed high rates of resistance to four or more antibiotics, 100% resistance to sulfadiazine and a high percentage of strains with the resistance profile of Salm. Typhimurium DT 104, two of them with this phage type (determined by PCR). A relationship between some clusters and their resistance and virulence profiles was detected, each cluster having the same profile. Conclusions: This study showed high‐antibiotic resistance of the Salmonella strains investigated, and the presence of multidrug‐resistant Salm. Typhimurium DT104 in infections of Portuguese children. Significance and Impact of the Study: Study is based on regarding the increase in antibiotic resistance by Salmonella strains isolated from infections in Portuguese children and on the presence of Salm. Typhimurium DT 104 circulating in Portugal.     

Predation of human pathogens by the predatory bacteria Micavibrio aeruginosavorus and Bdellovibrio bacteriovorus

Aims: The focus of this study was to evaluate the potential use of the predatory bacteria Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus to control the pathogens associated with human infection. Methods and Results: By coculturing B. bacteriovorus 109J and M. aeruginosavorus ARL‐13 with selected pathogens, we have demonstrated that predatory bacteria are able to attack bacteria from the genus Acinetobacter, Aeromonas, Bordetella, Burkholderia, Citrobacter, Enterobacter, Escherichia, Klebsiella, Listonella, Morganella, Proteus, Pseudomonas, Salmonella, Serratia, Shigella, Vibrio and Yersinia. Predation was measured in single and multispecies microbial cultures as well as on monolayer and multilayer preformed biofilms. Additional experiments aimed at assessing the optimal predation characteristics of M. aeruginosavorus demonstrated that the predator is able to prey at temperatures of 25–37°C but is unable to prey under oxygen‐limiting conditions. In addition, an increase in M. aeruginosavorus ARL‐13 prey range was also observed. Conclusions: Bdellovibrio bacteriovorus and M. aeruginosavorus have an ability to prey and reduce many of the multidrug‐resistant pathogens associated with human infection. Significance and Impact of the Study: Infectious complications caused by micro‐organisms that have become resistant to drug therapy are an increasing problem in medicine, with more infections becoming difficult to treat using traditional antimicrobial agents. The work presented here highlights the potential use of predatory bacteria as a biological‐based agent for eradicating multidrug‐resistant bacteria, with the hope of paving the way for future studies in animal models.     

Microbiological quality of grey-mullet roe

The Greek grey-mullet roe is produced from the fully developed gonads of the female mullet (Mugil cephalus) couth in lagoons during their reproductive migration. The traditional processing method of the roe includes, air drying, salting, shape formation and covering with multiple layers of natural beeswax for preservation and distribution. Fish Roe brands have been a staple in local diet and is increasingly becoming popular in the international market. As a ready-to-eat food it’s microbial quality should be of concern for the protection of consumers health. In this study, 48 samples of fish roe, just before waxing, were collected from various local processors for microbiological examination by using selective media and incubated under aerobic and anaerobic conditions. The identification of the bacteria was carried out according to the Bergey’s manual. Microscopic examination of Gram stained cells, catalase, oxidase and biochemical tests were performed when necessary to further identify.V. parahaemolyticus, Vibrio spp., Salmonella spp., and Aeromonas hydrophila were detected in one sample (2%). Shigella spp., and Flavobacterium spp. in two samples (4%), Clotriduim perfringens (vegetative forms), E. coli, and spores of Bacillus spp., were detected in three samples (6%), Staphylococcus aureus in four samples (8%). Various Micrococcus spp., and spores of C. perfringens in 16% and 35% of the samples respectively. From the Listeria genus, only the species Listeria innocua, Listeria welshimeri, Listeria seeligeri Listeria ivanovii and Listeria grayi were recovered from 2 to 10% of the samples.Microbiological analyses revealed the presence of a small number of pathogens in grey-mullet roe samples which are in accordance with the findings of similar studies. Traditional processing of the fish roe, seems inadequate to ensure the food safety and even waxing isn’t expected to fully protect them against facultative anaerobes with salt tolerance. Therefore, additional measures should be taken during processing and marketing of fish roe to minimize potential health risks for the consumers.     

Physical, chemical and microbiological quality of ice used to cool drinks and foods in Greece and its public health implications

Ice used for direct human consumption or to preserve foods and cool down drinks can be contaminated with pathogenic microorganisms and may potentially become a vehicle for consumer’s infection. To evaluate physical, chemical and microbiological quality of commercial ice and ice used for fish and seafood, 100 ice samples collected at 10 different retail points in the region of Epirus were studied. The following microbiological parameters were determined: Total coliforms, fecal coliforms, Salmonella spp., Shigella spp., Yersinia spp., Escherichia coli, Campylobacter sp., Vibrio cholerae, Aeromonas spp., Pseudomonas aeruginosa and Clostridium perfringens.E. coli was detected in 22% and coliforms were detected in 31% of samples. Samples in which coliforms were detected fail to meet the microbiological criteria specified by the drinking water legislation.Aeromonas spp., Shigella spp., Campylobacter sp. and V. cholerae were not detected. Spore forms of C. perfringens were prevalent at 35% and the psychotropic bacterium’s P. aeruginosa and Yersinia spp. were found only at three samples each.The presence of large numbers of coliforms as well as of other pathogenic strains suggested that commercial ice and ice used to make cool drinks or in preservation of fish and seafood may represent a potential hazard to the consumer. In view of the results reported herein, it is highly recommended that national regulatory guidelines should be established for the production of ice as long as regular inspections.     

Salmonella spp., Vibrio spp., Clostridium perfringens, and Plesiomonas shigelloides in Marine and Freshwater Invertebrates from Coastal California Ecosystems

The coastal ecosystems of California are highly utilized by humans and animals, but the ecology of fecal bacteria at the land–sea interface is not well understood. This study evaluated the distribution of potentially pathogenic bacteria in invertebrates from linked marine, estuarine, and freshwater ecosystems in central California. A variety of filter-feeding clams, mussels, worms, and crab tissues were selectively cultured for Salmonella spp., Campylobacter spp., Escherichia coli-O157, Clostridium perfringens, Plesiomonas shigelloides, and Vibrio spp. A longitudinal study assessed environmental risk factors for detecting these bacterial species in sentinel mussel batches. Putative risk factors included mussel collection near higher risk areas for livestock or human sewage exposure, adjacent human population density, season, recent precipitation, water temperature, water type, bivalve type, and freshwater outflow exposure. Bacteria detected in invertebrates included Salmonella spp., C. perfringens, P. shigelloides, Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio alginolyticus. Overall, 80% of mussel batches were culture positive for at least one of the bacterial species, although the pathogens Campylobacter, E. coli-O157, and Salmonella were not detected. Many of the same bacterial species were also cultured from upstream estuarine and riverine invertebrates. Exposure to human sewage sources, recent precipitation, and water temperature were significant risk factors for bacterial detection in sentinel mussel batches. These findings are consistent with the hypothesis that filter-feeding invertebrates along the coast concentrate fecal bacteria flowing from land to sea and show that the relationships between anthropogenic effects on coastal ecosystems and the environmental niches of fecal bacteria are complex and dynamic.     

Microbiological quality of pork meat from local Hong Kong markets

Over a 3-week period, samples of fresh, chopped, pork meat were taken every morning and afternoon from 50 meat stalls. Microbiological examination revealed that the samples had (c.f.u./g): total microbes, 1×10³ to 2.14×10⁶; mean probable numbers of coliforms and Escherichia coli, 1.51×10³ to 1.15×10⁴; and yeasts and moulds, 0 to 1.28×10⁴. Salmonella, found in 32 samples from 21 stalls, were serotyped as B (three samples), C1 (four) or E (25). No Campylobacter were found. Because microbial growth and/or contamination of the meat occurred during the day, samples taken in the afternoon had greater total counts (P<0.05) and contained detectable numbers of Salmonella more frequently (42% versus 22%) than those taken in the morning.The author is with the Department of Biology and Chemistry, City Polytechnic of Hong Kong, 83 Tat Chee Ave, Kowloon, Hong Kong     

Heterodisaccharide 4-O-(N-acetyl-β-D-glucosaminyl)-D-glucosamine is an effective chemotactic attractant for Vibrio bacteria that produce chitin oligosaccharide deacetylase

Aims: To investigate the attractant effect of 4‐O‐(N‐acetyl‐β‐d ‐glucosaminyl)‐d ‐glucosamine (GlcNAc‐GlcN) in the chemotaxis of Vibrio bacteria that produce carbohydrate esterase (CE) family 4 chitin oligosaccharide deacetylase (COD), an enzyme that catalyzes the production of GlcNAc‐GlcN from N,N′‐diacetylchitobiose (GlcNAc)₂. Methods and Results: The chemotactic effect of disaccharides from chitin on several strains of Vibrio bacteria was investigated using an agar gel lane‐migration method. The results demonstrated that GlcNAc‐GlcN functions as an effective chemoattractant in the CE family 4 COD‐producing vibrios, Vibrio parahaemolyticus and Vibrio alginolyticus. In contrast, this phenomenon was not observed in Vibrio nereis or Vibrio furnissii, which lack genes encoding this enzyme. From transmission electron microscope observation of V. parahaemolyticus cells following the chemotaxis assay, GlcNAc‐GlcN appears to stimulate polar flagellum rotation. Conclusions: GlcNAc‐GlcN is a specific chemoattractant for the CE family 4 COD‐producing vibrios, V. parahaemolyticus and V. alginolyticus. Significance and Impact of the Study: It was clarified for the first time that GlcNAc‐GlcN functions as a signalling molecule in the chemotaxis of Vibrio bacteria that have an ability to produce CE family 4 COD, which generate GlcNAc‐GlcN from (GlcNAc)₂.