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Microbial Safety (microbial + safety)
Selected AbstractsA review of modified atmosphere packaging of fish and fishery products , significance of microbial growth, activities and safetyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2002Morten Sivertsvik Modified atmosphere packaging (MAP) extends shelf-life of most fishery products by inhibiting bacterial growth and oxidative reactions. The achievable extension of shelf-life depends on species, fat content, initial microbial population, gas mixture, the ratio of gas volume to product volume, and most importantly, storage temperature. The shelf-life of fishery products is usually limited by microbial activity, although for some fatty fishes or at superchilled storage, it can be limited by nonmicrobial activity. Packaging of fishery products under modified atmospheres (MA) increases shelf-life compared with those packaged under air, but confers little or no additional shelf-life increase compared with vacuum packaging. The specific spoilage organism (SSO) of MA packaged cod at 0 °C has been found to be Photobacterium phosphoreum. Whether or not this bacterium is the general SSO for all marine temperate fishes at different storage temperatures and under various CO2/N2/O2 mixtures needs to be resolved. Without proper control of storage temperature, the benefits of MAP may be lost. Higher temperatures inevitably lead to less dissolved CO2 in the product and consequently loss of inhibitory effect, which may result in higher microbial and enzymatic activity, and uncertainties concerning the microbial safety, as food-borne pathogens might be present in the product. [source] MICROBIOLOGICAL AND PHYSICOCHEMICAL CHARACTERIZATION OF NATURAL FERMENTED CAMEL MEAT SAUSAGEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2008JAZILA EL MALTI ABSTRACT In this study, fermentations of camel meat were followed by analyzing the microbiological and physicochemical aspects of this product. The sausages were characterized by an important microbial activity of lactic acid bacteria that resulted in a product with a final pH of about 5.06. No Listeria monocytogenes, Salmonella spp. and sulfite-reducing clostridia were ever isolated from the raw materials or the fermented sausages during the maturation, underlining the safety of this product. The final water activity of the product was 0.91. Identification showed that the majority of lactobacilli isolated from de Man,Rogosa,Sharpe agar strains were assigned to the species of Lactobacillus plantarum. PRACTICAL APPLICATIONS The production of fermented foods is based on the use of starter cultures, for instance lactic acid bacteria that initiate rapid acidification of the raw material. They contribute to the microbial safety or offer one or more organoleptic, technological, nutritional, or health advantages. Also, their production of acetic acid, ethanol, aroma compounds, bacteriocins, exopolysaccharides, and several enzymes is of importance. In this way they enhance shelf life and microbial safety, improve texture, and contribute to the pleasant sensory profile of the end product. [source] PROTECTIVE CULTURES USED FOR THE BIOPRESERVATION OF HORSE MEAT FERMENTED SAUSAGE: MICROBIAL AND PHYSICOCHEMICAL CHARACTERIZATIONJOURNAL OF FOOD SAFETY, Issue 3 2008JAZILA EL MALTI ABSTRACT In this paper, 150 isolates, originating from horse meat, were subjected to step-by-step screening and characterization to search for potential protective cultures to be used in the meat industry. Isolates were first tested on their homofermentative and salt tolerance. Second, the antibacterial capacities toward Listeria monocytogenes were determined in an agar spot test. In total, 50% of the tested isolates were inhibitory toward Listeria monocytogenes. However, only 12 isolates produced a bacteriocin. Finally, three isolates with the strong bacteriocin activity were evaluated on their competitive nature by comparing their growth rate, acidifying character and lactic acid production at 15C under anaerobic conditions in a liquid broth. All three isolates combined a fast growth rate with a deep and rapid acidification caused by the production of high levels of lactic acid. Lactobacillus sakei was used as starter culture for producing sausage horse meat. In this study, fermentations were followed analyzing the microbiological and physicochemical aspects of this product. The sausages were characterized by an important microbial activity of lactic acid bacteria that resulted in a product with a final pH of about 4.56. No Listeria monocytogenes, Salmonella spp. or sulfite reducing clostridia were ever isolated from the raw materials or the fermented sausages during the maturation, underlining the microbial safety of this product. The final water activity of the product was 0.85. Starter cultures showed that Lactobacillus sakei was really efficient in reducing the amine production since this strain caused a quick pH drop during sausage fermentation. PRACTICAL APPLICATIONS A starter culture can be defined as a microbial preparation of large numbers of cells of at least one microorganism to be added to a raw material to produce a fermented food by accelerating and steering its fermentation process. The group of lactic acid bacteria (LAB) occupies a central role in these processes, and has a long and safe history of application and consumption in the production of fermented foods and beverages. They cause rapid acidification of the raw material through the production of organic acids, mainly lactic acid. Also, their production of acetic acid, ethanol, aroma compounds, bacteriocins, exopolysaccharides and several enzymes is of importance. The main reason for suitability of LAB is their natural origin, and they can contribute to food safety and/or offer one or more organoleptic, technological, nutritional or health advantages. [source] Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on Stored Iceberg Lettuce by Aqueous Chlorine Dioxide TreatmentJOURNAL OF FOOD SCIENCE, Issue 9 2008Yun-Jung Kim ABSTRACT:, Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes in iceberg lettuce by aqueous chlorine dioxide (ClO2) treatment was evaluated. Iceberg lettuce samples were inoculated with approximately 7 log CFU/g of E. coli O157:H7, S. typhimurium, and L. monocytogenes. Iceberg lettuce samples were then treated with 0, 5, 10, or 50 ppm ClO2 solution and stored at 4 °C. Aqueous ClO2 treatment significantly decreased the populations of pathogenic bacteria on shredded lettuce (P < 0.05). In particular, 50 ppm ClO2 treatment reduced E. coli O157:H7, S. typhimurium, and L. monocytogenes by 1.44, 1.95, and 1.20 log CFU/g, respectively. The D10 -values of E. coli O157:H7, S. typhimurium, and L. monocytogenes in shredded lettuce were 11, 26, and 42 ppm, respectively. The effect of aqueous ClO2 treatment on the growth of pathogenic bacteria during storage was evaluated, and a decrease in the population size of these pathogenic bacteria was observed. Additionally, aqueous ClO2 treatment did not affect the color of lettuce during storage. These results suggest that aqueous ClO2 treatment can be used to improve the microbial safety of shredded lettuce during storage. [source] Retention of Quality and Nutritional Value of 13 Fresh-Cut Vegetables Treated with Low-Dose RadiationJOURNAL OF FOOD SCIENCE, Issue 7 2008X. Fan ABSTRACT:, Improving the microbial safety while maintaining quality of fresh fruits and vegetables will increase consumer confidence in fresh produce. This study was conducted to investigate the effects of irradiation at 1 kGy, a dose that potentially inactivates E. coli O157:H7 by 5 logs, on the quality of 13 common fresh-cut vegetables: iceberg, romaine, green and red leaf lettuce, spinach, tomato, cilantro, parsley, green onion, carrot, broccoli, red cabbage, and celery. The results showed that the appearance of irradiated samples was similar to the nonirradiated ones except that irradiated carrots, celery, cilantro, and green onions had higher appearance scores than corresponding nonirradiated vegetables. There was no difference in the instrumental texture between irradiated samples and nonirradiated ones. The aroma of several irradiated vegetables was significantly better than controls after 14-d storage, because these control samples decayed or senesced. The 1 kGy irradiation did not affect vitamin C content of most vegetables; however, irradiated green and red leaf lettuce had 24% to 53% lower vitamin C contents than the controls. Our results suggest that most fresh-cut fruits and vegetables tested can tolerate up to 1 kGy irradiation without significant losses in any of the quality attributes. [source] Effectiveness of Some Natural Antimicrobial Compounds in Controlling Pathogen or Spoilage Bacteria in Lightly Fermented Chinese CabbageJOURNAL OF FOOD SCIENCE, Issue 9 2005Yasuhiro Inatsu ABSTRACT: This study was designed to evaluate the bactericidal or bacteriostatic effect of chitosan, an allyl isothiocyanate (AIT) product, and nisin for the artificially inoculated pathogenic bacteria (Escherichia coli, Salmonella Enteritidis, Staphylococcus aureus, and Listeria monocytogenes) or natural microflora of fermented Chinese cabbage. Addition of 0.1% chitosan decreased the population of pathogens from 0.7 to 1.7 log colony-forming units (CFU)/g after 4 d of storage at 10 °C. The bactericidal activity of chitosan was found to be stronger than that of nisin (0.05 mg/g). Addition of 0.2% of the AIT product (containing AIT and hop extract) exhibited a bacteriostatic effect. However, a combination of AIT product and chitosan enhanced bactericidal efficacy against L. monocytogenes. The addition of chitosan or AIT product was observed to suppress the populations of mesophilic and coliform bacteria during storage at 10 °C for 4 d. Moreover, the use of chitosan or the AIT product did not change the sensory quality of the lightly fermented vegetable. Therefore, these results suggest that chitosan or the AIT product could be useful to improve the microbial safety and quality of lightly fermented vegetable. [source] Microbiological survey of prepackaged pâté and ham in New ZealandLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2005T.L. Wong Abstract Aims:, To gauge the effectiveness of pâté and ham manufacturers' management of the microbial safety and quality of their products. Methods and Results:, A survey of 60 batches of prepackaged pâté showed that 41·7% of the batches had aerobic plate counts (APC) exceeding 105 CFU g,1, one of pâté sample contained a Bacillus cereus count of >5000 CFU g,1 and another contained 1700 CFU g,1 of Listeria monocytogenes. No other pathogens were isolated from any of the samples. The survey of prepackaged ham showed that only 1% (1/104) of the ham samples were positive for L. monocytogenes (50 CFU g,1). Conclusions:, The presence of microbial hazards in these foods has generally declined since the early 1990s in New Zealand. Noncomplying APC levels may be due to an over-estimation of product shelf life or poor food handling practices during manufacture. Significance and Impact of the Study:, Few of the samples tested contained pathogens at significant levels. The prevalences of L. monocytogenes in pâté and ham were low. The presence of 1700 CFU g,1 of L. monocytogenes in a pâté sample indicates that occasionally, the population can be exposed to levels of L. monocytogenes above the zero tolerance level set in New Zealand. [source] Quality changes of treated fresh-cut tropical fruits in rigid modified atmosphere packaging containersPACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2007Vanee Chonhenchob Abstract There has been increasing demand for various fresh-cut tropical fruits. However, their short shelf-life has limited the market increase of this product. Quality changes (firmness, colour, total soluble solids (TSS), titratable acidity (TA), sensory quality and microbial safety) of fresh-cut mangoes, pineapples, melons and mixes of these fruits were evaluated. Chemical treatments to reduce browning, firmness loss and decay of fresh-cut tropical fruits were investigated. The most effective agents for fresh-cut mangoes, pineapples and melons were 0.1m ascorbic acid, 0.2m ascorbic acid and 0.2m ascorbic acid + 0.2m calcium chloride, respectively. Fresh-cut tropical fruits were packaged in various rigid containers (PET, OPS and OPLA). Gas composition in the package headspace and time to reach steady-state condition varied among fresh-cut packaging systems and affected their quality and shelf-life. The effects of package permeability of O2 and CO2 on quality and shelf-life of the fresh-cut products are discussed. Extended shelf-life was observed in fresh-cut mangoes, pineapples and mixes packaged in PET due to reduced O2 and elevated CO2 atmosphere. A modified atmosphere of 6% O2 and 14% CO2 achieved in PET extended the shelf-life of fresh-cut pineapples from 6 to 13 days. Accumulation of CO2 may impart an off-odour of fresh-cut fruits. The results suggested that the shelf-life of fresh-cut fruits could be extended by using proper rigid containers. Suitable mixes to create optimal equilibrium modified atmosphere had a potential to extend shelf-life of short shelf-life fresh-cut tropical fruits. Copyright © 2006 John Wiley & Sons, Ltd. [source] Innovations in the Development and Application of Edible Coatings for Fresh and Minimally Processed Fruits and VegetablesCOMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY, Issue 3 2007Daniel Lin ABSTRACT:, One of the major growth segments in the food retail industry is fresh and minimally processed fruits and vegetables. This new market trend has thus increased the demands to the food industry for seeking new strategies to increase storability and shelf life and to enhance microbial safety of fresh produce. The technology of edible coatings has been considered as one of the potential approaches for meeting this demand. Edible coatings from renewable sources, including lipids, polysaccharides, and proteins, can function as barriers to water vapor, gases, and other solutes and also as carriers of many functional ingredients, such as antimicrobial and antioxidant agents, thus enhancing quality and extending shelf life of fresh and minimally processed fruits and vegetables. This review discusses the rationale of using edible coatings on fresh and minimally processed produce, the challenges in developing effective coatings that meet the specific criteria of fruits and vegetables, the recent advances in the development of coating technology, the analytical techniques for measuring some important coating functionalities, and future research needs for supporting a broad range of commercial applications. [source] | ||||||||||