Detection of Listeria monocytogenes in Commercially Broken Unpasteurized Liquid Egg in Japan

2009 ◽  
Vol 72 (1) ◽  
pp. 178-181 ◽  
Author(s):  
MIHO OHKOCHI ◽  
MIYUKI NAKAZAWA ◽  
NOBUHIRO SASHIHARA

Unpasteurized liquid whole-egg samples were collected from six and seven commercial establishments across Japan in 1993 and 1994 and in 2005, respectively. The samples were tested for the presence of Listeria spp. and Listeria monocytogenes. Detection rates of the Listeria spp. were greatly different among the egg-breaking facilities, with a range of 8 to 55%. There was no significant difference in the contamination rate between the samples from 1993 and 1994 and from 2005. L. monocytogenes was isolated from 2 of 487 (0.4%) samples in 1993 and 1994, and 2 of 316 (0.6%) samples in 2005. These detection rates are lower than known detection rates of other livestock products (5.1 to 42%). In 2005, the L. monocytogenes–positive samples were quantified by a most-probable-number counting experiment, and the contamination levels were below 7.5 organisms per 25 g of sample. D55°C-values of 0.59 to 4.08/min were determined for L. monocytogenes isolated in this study. This heat tolerance is in a good agreement with past reports, and slightly higher than that of Salmonella. This study suggests that the legal pasteurization condition of liquid egg is sufficient to ensure microbial safety against L. monocytogenes because the contamination rate and its level are considerably low.

2017 ◽  
Vol 100 (2) ◽  
pp. 470-473
Author(s):  
Naoko Kamisaki-Horikoshi ◽  
Yukio Okada ◽  
Kazuko Takeshita ◽  
Makoto Takada ◽  
Shinichi Kawamoto ◽  
...  

Abstract In 2009, the enrichment broth TA10 was released for simultaneous recovery of Salmonella spp., Listeria monocytogenes, and Escherichia coli O157:H7. This medium was compared with other Salmonella enrichment broths [lactose (LAC) broth, buffered peptone water (BPW), and universal pre-enrichment (UP) broth] for the recovery of heat- and freeze-injured Salmonella spp. in beef by the conventional culture method. There was a significant difference between TA10 and LAC enrichment broths for detecting injured Salmonella spp. In this study, the International Organization for Standardization Listeria pre-enrichment broth (Half-Fraser/Fraser) was compared with TA10 broth for the recovery of L. monocytogenes from ground beef. Ground beef samples were contaminated with single Listeria serovars at levels of 0.096 to 0.001 most probable number/g. Twenty 25 g test portions of the contaminated ground beef were pre-enriched in each broth, and the ISO-11290-1 Listeria official isolation protocol was used thereafter. There was a significant difference between TA10 broth (48 h) and Half-Fraser/Fraser broth (72 h) in the recovery of L. monocytogenes. In addition, the incubation time for TA10 broth was shorter than for Half-Fraser/Fraser broth. The results indicate that TA10 broth should be used instead of Half-Fraser/Fraser broth for analysis of beef that may be contaminated with very low levels of L. monocytogenes.


2011 ◽  
Vol 94 (3) ◽  
pp. 857-862 ◽  
Author(s):  
Naoko Kamisaki -Horikoshi ◽  
Yukio Okada ◽  
Kazuko Takeshita ◽  
Takashi Sameshima ◽  
Susumu Kawasaki ◽  
...  

Abstract The Bacteriological Analytical Manual (BAM) Salmonella pre-enrichment broth [lactose (LAC) broth], buffered peptone water, and universal pre-enrichment (UP) broth were compared with TA10 broth, developed in our laboratory, for recovery of heat- and freeze-injured Salmonella (55°C for 2–20 min and –20°C for 2 months, respectively) from beef. Beef samples were contaminated with single Salmonella serovars, and contamination levels of 0.44 to <0.001 most probable number (MPN)/g and 0.74 to 0.14 MPN/g were used for heat- and freezing-induced injury studies, respectively. Twenty test portions (25 g) of the contaminated beef were pre-enriched in each broth, and the BAM Salmonella culture method was used thereafter. There was a significant difference (χ2 = 7.73) in recovery of heat-injured Salmonella between TA10 broth and LAC broth, 189 (67.5%) versus 156 (55.7%) positive samples, respectively, determined by plating onto selective agars and identification by biochemical tests. For the recovery of freeze-injured Salmonella, there was a significant difference (χ2 = 24.7) between TA10 and LAC broth, 189 (72.7%) versus 133 (51.2%) positive samples, respectively. TA10 broth was more effective than LAC broth and UP broth for recovery of freeze-injured Salmonella. The results indicate that TA10 broth should be used instead of LAC broth for testing of beef that may be contaminated with heat- and freeze-injured Salmonella spp.


1997 ◽  
Vol 60 (4) ◽  
pp. 424-425 ◽  
Author(s):  
SUSAN A. McCARTHY

The U.S. Food and Drug Administration most probable number (MPN) method and the Listertest™ (immunomagnetic capture) were used to enumerate Listeria monocytogenes on laboratory-inoculated cooked crabmeat (Callinectus sapidus) and cold-smoked salmon (Salmo salar). The products were inoculated with <1.0 to 4.0 log CFU of L. monocytogenes per g and analyzed immediately. In the analyses of crabmeat, the results obtained by the MPN method were significantly lower (P < 0.05) than counts produced by the Listertest™. There was no significant difference (P < 0.05) between results produced by MPN and the Listertest™ in analyses of smoked salmon. The methods had the same variance in the quantitation of L. monocytogenes in these seafood products.


2015 ◽  
Vol 78 (11) ◽  
pp. 1945-1953 ◽  
Author(s):  
YUE CUI ◽  
HUSNU S. GURAN ◽  
MARK A. HARRISON ◽  
CHARLES L. HOFACRE ◽  
WALID Q. ALALI

The objective of this study was to determine Salmonella levels (presence and numbers) in turkey drumstick bone, spleen, and neck skin samples in relation to Salmonella contamination levels in ground turkey at the flock level. Over a 10-month period, a total of 300 samples of each turkey part (i.e., neck skin, spleen, and drumstick) from 20 flocks were collected at a commercial turkey processing plant after the evisceration step. Turkey flocks included in this study were classified as “targeted” and “nontargeted” based on the company's historical ground turkey contamination data. A flock that originated from a turkey farm that had previously produced one or more flocks with ≥20% Salmonella prevalence in ground turkey was labeled as a targeted flock (n=13). The remaining seven flocks with <20% prevalence were labeled as nontargeted. All samples collected were tested for Salmonella presence and numbers by using most-probable-number and selective enrichment methods. Further genotypic analysis (pulsed-field gel electrophoresis) of the isolates was performed. Ground turkey samples were collected and analyzed for Salmonella levels by the cooperating turkey company. The outside surface of bone and spleen were sterilized prior to Salmonella analysis. The overall Salmonella prevalence in neck skin, drumstick bone, spleen, and ground turkey samples was 42.0, 9.3, 6.7, and 14.5%, respectively. Salmonella prevalence in neck skin, spleen, drumstick bone, and ground turkey from the targeted flocks was significantly (P < 0.05) higher than those from nontargeted flocks. There was a significant relationship between Salmonella presence in neck skin (when most probable numbers were ≥2 log) and Salmonella-positive ground turkey lot. Based on our findings, Salmonella was detected internally in drumstick bones and spleens at low levels, whereas Salmonella presence at higher levels in neck skin may indicate a flock with greater potential for Salmonella contamination of ground turkey.


2003 ◽  
Vol 66 (3) ◽  
pp. 390-395 ◽  
Author(s):  
HAYDEN K. CRESSY ◽  
ALISTAIR R. JERRETT ◽  
CAROLYN M. OSBORNE ◽  
PHIL J. BREMER

The use of multiple freeze (−20°C)–thaw cycles in combination with isoeugenol and polysorbate 80 was investigated as a method for the reduction of numbers of Listeria monocytogenes cells in a bacteriological medium. Three freeze (1 h, −20°C)–thaw cycles in the presence of isoeugenol at concentrations of 0, 100, and 300 ppm resulted in average L. monocytogenes reductions of 0.69, 2.65, and 3.3 log10 MPN (most probable number) per ml, respectively. Increasing the number of freeze–thaw cycles further decreased cell numbers, with reductions of nearly 5 log10 MPN/ml being obtained with six freeze-thaw cycles. Freeze–thaw cycles were effective in reducing cell numbers at isoeugenol concentrations down to 25 ppm. Rapid freezing rates with liquid nitrogen were found to be less effective in reducing numbers of L. monocytogenes cells. Two rapid freeze–thaw cycles in the presence of 100 ppm isoeugenol and polysorbate 80 resulted in a reduction of 1.45 log10 MPN/ml. Two freezing (−20°C) cycles involving slow freezing and thawing rates with samples being held frozen for 6 h for each cycle resulted in reductions larger than those obtained with faster freezing rates. It was found that complete thawing in freeze-thaw cycles was not necessary to achieve bactericidal action. The application of multiple freeze-thaw cycles in combination with low concentrations of isoeugenol could effectively reduce numbers of L. monocytogenes cells in bacteriological media.


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Ruth Adi Agyo ◽  
Raph Agbo Ofukwu ◽  
Anthony Ekle J. Okoh ◽  
Charity A. Agada

Aim: This study aimed at examined the presence of coliform bacteria in private wells and boreholes (BH) in peri-urban areas of Makurdi, Benue State, Nigeria, using the approaches of most probable number (MPN) index and coliform count. Materials and Methods: Seven hundred and sixty-eight water samples were randomly collected during a 1-year period from non-cased wells, burn brick cased wells (BBW), concrete cased wells, and BH in four locations; A, B, C, and D during the wet and dry seasons. One liter of water was obtained from each well at every visit to the four sites, and eight water samples were collected from each visit. The samples were analyzed using multiple tube fermentation methods and pour plate techniques to determine the MPN of coliform/100 ml of water, reading from the MPN statistics table. Results: One-way analysis of variance statistics was applied using Duncan's new multiple range test to separate the means where there was a significant difference. The result revealed that the MPN index and total coliform counts in all the wells in the locations were above the World Health Organization (WHO) permissible limit for potable water. The highest MPN index of 54.807 was recorded in Location A and followed by 42.679 in Location B. The MPN index in Locations C and D was 36.740 and 30.943, respectively. There was significantly (p=0.000) higher total coliform count in the wet season (41.48±7.09) than in the dry season (38.33±2.83). Conclusion: This study shows the presence of coliform bacteria isolates in all the wells and BH that exceeded the WHO permissible limits for drinking water. The water from these sources is unsafe for drinking except after dosing with appropriate germicides. Sensitization of the population on the actions they can take to make the water safe for domestic use is suggested.


2019 ◽  
Vol 1 ◽  
pp. 1-8
Author(s):  
E M Mbaawuaga ◽  
W C Agber ◽  
M W Kar

Assessment of the efficacy of Water-Care in the treatment of water to safe health level was carried out on water samples from different water sources within six populated communities of Makurdi Metropolis. Thirty six (36) water samples were collected and treated with WaterCare based on the product manufacturer’s instructions. Treated water stored for 30 minutes and 24 hours were tested for coliforms using Multiple Tube Fermentation technique. Analysis of variance (ANOVA) was used with the Tukey Honestly Significant Difference (HSD) for multiple comparisons of the data variables. Most probable Number (MPN) of coliforms /100mL of sampled water ranged from 43 to >1,100cfu/100ml. Mean MPN of treated water for30 minutes and 24 hours interval was 37.7±33.0cfu/100ml and 16.17±14.8cfu/100ml respectively. Improved/deep sources such as boreholes show 3cfu/100ml and 0cfu/100ml respectively for 30 minutes and 24 hours treatment while unimproved/shallow sources such as wells show ≤120 cfu/100ml and ≤53 cfu/100ml respectively for 30 minutes and 24 hour interval. A significant difference between treated samples and the untreated was observed (F = 6.321, P = 0.005). Tukey multiple comparison test revealed that MPN index/100ml in the water samples was significantly lower (P =0.015, P =0.009) after treating for 30 minutes and 24 hour time interval respectively as compared to untreated water. But there was no significant difference between the 30 minute and 24 hour time interval (P =0.970). The study found that, drinking water sources in Makurdi Township were heavily contaminated, and that 30 minutes and 24 hours’ time interval was not a sufficient time for total elimination of bacteria contaminants after treatment with WaterCare. Future research should ascertain the actual treatment time for inactivation of all bacteria in water treated with WaterCare.


1992 ◽  
Vol 55 (12) ◽  
pp. 946-951 ◽  
Author(s):  
J. M. FARBER ◽  
E. DALEY ◽  
F. COATES ◽  
D. B. EMMONS ◽  
R. McKELLAR

Heat resistance experiments were carried out with Listeria monocytogenes which had been grown at three different temperatures (30, 39, and 43°C). Heated whole milk was inoculated with L. monocytogenes and then passed through a high-temperature short-time system at 72, 69, 66, and 63°C for a minimum holding time of 16.2 s. Heated cells were recovered both aerobically and anaerobically using four different methods: direct plating, most probable number, cold enrichment, and warm enrichment. Significant differences in recovery of L. monocytogenes were observed depending on the growth temperature. Cells grown at 43, 39, or 30°C, held 1 d at 4°C, and then heated at 69°C showed an overall decrease in numbers of approximately 2.1, 2.8, and 4.1 logs, respectively. Cells grown at 39°C and then held 3 d at 4°C appeared to be the most heat sensitive. Although cells grown at 43 and 39°C were capable of surviving at the minimum high-temperature short-time temperature (72°C), those grown at 30°C were not. In some instances, anaerobic incubation enhanced the recovery of L. monocytogenes, as compared to cells recovered aerobically, although these differences were not statistically significant. While L. monocytogenes can survive minimum pasteurization treatment (71.7°C/16 s) under certain conditions, common methods of handling, processing, and storing fluid milk will provide an adequate margin of safety.


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