Living with <i>Listeria</i>

Prentice, G. A.

doi:10.1111/j.1471-0307.1989.tb02154.x

Cited by 6 publications

(4 citation statements)

References 11 publications

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“…Staph. aureus may produce toxin and cause toxication for humans, however, around 7 log/g are required [22]. Therefore, all counts from examined cheeses were lower than the toxin production level of the population.…”

Section: Microbial Countsmentioning

confidence: 89%

Microbiological and biochemical changes in herby cheese during ripening

Çoşkun¹

1998

Nahrung

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The aim of this study was to determine and compare the microbiological, biochemical and sensory characteristics of herby cheese made with two different methods. In the first method (M1), milk and herbs were pasteurized at 65°C for 30 min, and Lactococcus lactis subsp. lactis and L. lactis subsp. cremoris were added as starter culture at an inoculum ratio of 1.5%. In the second method (M2), the conventional cheesemaking was applied. Microbiological and biochemical changes were monitored throughout the ripening period of 90 days. Samples were taken from cheeses on days 1, 15, 30, 60, and 90. At the end of ripening, sensory characteristics of cheeses manufactured with both methods were evaluated. The obtained results suggested that most changes in pH, titratable acidity, and dry matter contents of cheese varieties were not found to differ statistically significant, but the difference in salt content was significant (P < 0.01). Total aerobic count, lactic acid bacteria, Staphylococcus aureus, coliforms, moulds, yeasts, proteolytic and lipolytic microorganism counts were lower in M1 cheese samples than those of M2 cheese samples (P < 0.01). The numbers of psychrotrophic microorganism in both cheese types were not found to differ significantly. Moreover, the results suggested that there were significant differences (P < 0.01) in the degrees of proteolysis and lipolysis of the cheese varieties. High proteolysis and lipolysis rates were monitored in the traditional cheese samples. However, there were no significant differences between the sensory characteristics of cheese samples.

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Section: Microbial Countsmentioning

confidence: 89%

Microbiological and biochemical changes in herby cheese during ripening

Çoşkun¹

1998

Nahrung

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“…In the early 1980s scientists recognized Listeria as a foodborne pathogen as human listerosis resulted from consuming food contaminated with this pathogen such as milk and dairy products, meat, poultry, vegetables, salads and seafood [3]. Moreover, L. monocytogenes has a saprophytic life and occurs widely in nature [4]. A variety of animals including domestic farm animals can carry the bacterium [5], and it can survive for long periods in a plant-soil environment [6].…”

Section: Introductionmentioning

confidence: 99%

Listeria spp. in the coastal environment of the Aqaba Gulf, Suez Gulf and the Red Sea

El‐Shenawy

El-Shenawy

2005

Epidemiol. Infect.

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Listeria monocytogenes is an important pathogen which causes an infection called listeriosis. Because of the high mortality rate (~30%) associated with listeriosis, and the widespread nature of the organism, it is a major concern for food and water microbiologists since it has been isolated from various types of foods, including seafood, as well as from the aqueous environment. To investigate the prevalence of this pathogen in the Aqaba Gulf (12 sites), Suez Gulf (14 sites) and Red Sea (14 sites), 200 water samples (collected during five sampling cruises in 2004), 40 fresh fish samples and 15 shellfish samples were analysed using the enrichment procedure and selective agar medium. All water samples were also examined for the presence Listeria innocua which was the most common of the Listeria spp. isolated, followed by L. monocytogenes, with a low incidence of the other species. During the whole year, the percentage of Listeria spp. and L. monocytogenes in 200 water samples was 20.5% (41 samples) and 13% (26 samples) respectively. In fresh fish (40 samples) it was 37% (15 samples) and 17.3% (7 samples) and in shellfish (15 samples) 53% (8 samples) and 33% (5 samples) respectively. In water samples, there was an association between the faecal contamination parameters and the presence of the pathogen; however, water salinity, temperature, dissolved oxygen and pH did not influence the occurrence of this bacterium. These results may help in the water-quality evaluation of the coastal environments of these regions.

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“…However, both media gave comparable results with the Scott A strain. Other selective media have been reported to have different recovery rates for isolation of L. monocytogenes from various foods and clinical specimens (8, 10, 13, 20). It is noteworthy that recovery of L. monocytogenes from food with ASLM was efficient, since a high number (-106 CFU/ml) of background microflora also was present.…”

Section: Resultsmentioning

confidence: 99%

Highly selective medium for isolation of Listeria monocytogenes from food

Al-zoreky

Sandine

1990

Appl Environ Microbiol

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A new selective medium (Al-Zoreky-Sandine listeria medium [ASLM]) was formulated to recover Listeria monocytogenes from food specimens; the medium completely inhibited common food microflora. Recognition of Listeria colonies is evident by black discoloration of the medium due to esculin hydrolysis without need for special illuminating equipment. The medium contains acriflavin, ceftazidime, and moxalactam as selective agents. Compared with Listeria Selective Agar, ASLM was equally effective in recovering L. monocytogenes. However, ASLM inhibited micrococci, enterococci, and gram-negative bacteria, especially a strain that mimicked L. monocytogenes on Listeria Selective Agar. The new medium was able to recover heat injured cells with only 15% less count than the nonselective medium. Recent food outbreaks of listeriosis (6, 9, 12, 15, 20) have emphasized the need for a highly selective medium to detect Listeria monocytogenes, a human and animal pathogen. Listeriosis has a mortality rate of up to 33% (5, 17) and is highest for pregnant women, infants, and immunocompromised persons. Fifty percent lethal doses of L. monocytogenes are as low as 5 cells for immunocompromised mice, whereas the 50% lethal dose for normal mice is 105 to 107 * Corresponding author. t Technical paper no. 9220, Oregon Agricultural Experiment Station.

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Living with Listeria

Cited by 6 publications

References 11 publications

Microbiological and biochemical changes in herby cheese during ripening

Microbiological and biochemical changes in herby cheese during ripening

Listeria spp. in the coastal environment of the Aqaba Gulf, Suez Gulf and the Red Sea

Highly selective medium for isolation of Listeria monocytogenes from food

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