Inactivation of Mycobacterium avium subsp. paratuberculosis during Cooking of Hamburger Patties

2013 ◽  
Vol 76 (7) ◽  
pp. 1194-1201 ◽  
Author(s):  
PHILIPP HAMMER ◽  
HANS-GEORG C. WALTE ◽  
SÖ NKE MATZEN ◽  
JANN HENSEL ◽  
CHRISTIAN KIESNER
Keyword(s):  
Mycobacterium Avium ◽  
Egg Yolk ◽  
Mycobacterium Avium Subsp ◽  
Most Probable Number ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Bacterial Reduction ◽  
Probable Number ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
Cooking Times

The role of Mycobacterium avium subsp. paratuberculosis (MAP) in Crohn's disease in humans has been debated for many years. Milk and milk products have been suggested as possible vectors for transmission since the beginning of this debate, whereas recent publications show that slaughtered cattle and their carcasses, meat, and organs can also serve as reservoirs for MAP transmission. The objective of this study was to generate heat-inactivation data for MAP during the cooking of hamburger patties. Hamburger patties of lean ground beef weighing 70 and 50 g were cooked for 6, 5, 4, 3, and 2 min, which were sterilized by irradiation and spiked with three different MAP strains at levels between 102 and 106 CFU/ml. Single-sided cooking with one flip was applied, and the temperatures within the patties were recorded by seven thermocouples. Counting of the surviving bacteria was performed by direct plating onto Herrold's egg yolk medium and a three-vial most-probable-number method by using modified Dubos medium. There was considerable variability in temperature throughout the patties during frying. In addition, the log reduction in MAP numbers showed strong variations. In patties weighing 70 g, considerable bacterial reduction of 4 log or larger could only be achieved after 6 min of cooking. For all other cooking times, the bacterial reduction was less than 2 log. Patties weighing 50 g showed a 5-log or larger reduction after cooking times of 5 and 6 min. To determine the inactivation kinetics, a log-linear regression model was used, showing a constant decrease of MAP numbers over cooking time.

scholarly journals Rapid Assessment of the Viability of Mycobacterium avium subsp. paratuberculosis Cells after Heat Treatment, Using an Optimized Phage Amplification Assay

2010 ◽  
Vol 76 (6) ◽  
pp. 1777-1782 ◽  
Author(s):  
Antonio Foddai ◽  
Christopher T. Elliott ◽  
Irene R. Grant
Keyword(s):  
Mycobacterium Avium ◽  
Thermal Inactivation ◽  
Rapid Assessment ◽  
Egg Yolk ◽  
Inactivation Kinetics ◽  
Complete Inactivation ◽  
Conventional Culture ◽  
Amplification Assay ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
Thermal Cycler

ABSTRACT Thermal inactivation experiments were carried out to assess the utility of a recently optimized phage amplification assay to accurately enumerate viable Mycobacterium avium subsp. paratuberculosis cells in milk. Ultra-heat-treated (UHT) whole milk was spiked with large numbers of M. avium subsp. paratuberculosis organisms (106 to 107 CFU/ml) and dispensed in 100-μl aliquots in thin-walled 200-μl PCR tubes. A Primus 96 advanced thermal cycler (Peqlab, Erlangen, Germany) was used to achieve the following time and temperature treatments: (i) 63°C for 3, 6, and 9 min; (ii) 68°C for 20, 40, and 60 s; and (iii) 72°C for 5, 10, 15, and 25 s. After thermal stress, the number of surviving M. avium subsp. paratuberculosis cells was assessed by both phage amplification assay and culture on Herrold's egg yolk medium (HEYM). A high correlation between PFU/ml and CFU/ml counts was observed for both unheated (r 2 = 0.943) and heated (r 2 = 0.971) M. avium subsp. paratuberculosis cells. D and z values obtained using the two types of counts were not significantly different (P > 0.05). The D 68°C, mean D 63°C, and D 72°C for four M. avium subsp. paratuberculosis strains were 81.8, 9.8, and 4.2 s, respectively, yielding a mean z value of 6.9°C. Complete inactivation of 106 to 107 CFU of M. avium subsp. paratuberculosis/ml milk was not observed for any of the time-temperature combinations studied; 5.2- to 6.6-log10 reductions in numbers were achieved depending on the temperature and time. Nonlinear thermal inactivation kinetics were consistently observed for this bacterium. This study confirms that the optimized phage assay can be employed in place of conventional culture on HEYM to speed up the acquisition of results (48 h instead of a minimum of 6 weeks) for inactivation experiments involving M. avium subsp. paratuberculosis-spiked samples.

scholarly journals Effective Heat Inactivation of Mycobacterium avium subsp. paratuberculosis in Raw Milk Contaminated with Naturally Infected Feces

2007 ◽  
Vol 73 (13) ◽  
pp. 4185-4190 ◽  
Author(s):  
Jan L. W. Rademaker ◽  
Marc M. M. Vissers ◽  
Meike C. te Giffel
Keyword(s):  
Mycobacterium Avium ◽  
Clinical Symptoms ◽  
Raw Milk ◽  
Pilot Scale ◽  
Holding Time ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Data Points ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
High Concentrations

ABSTRACT The effectiveness of high-temperature, short holding time (HTST) pasteurization and homogenization with respect to inactivation of Mycobacterium avium subsp. paratuberculosis was evaluated quantitatively. This allowed a detailed determination of inactivation kinetics. High concentrations of feces from cows with clinical symptoms of Johne's disease were used to contaminate raw milk in order to realistically mimic possible incidents most closely. Final M. avium subsp. paratuberculosis concentrations varying from 102 to 3.5 × 105 cells per ml raw milk were used. Heat treatments including industrial HTST were simulated on a pilot scale with 22 different time-temperature combinations, including 60 to 90°C at holding (mean residence) times of 6 to 15 s. Following 72°C and a holding time of 6 s, 70°C for 10 and 15 s, or under more stringent conditions, no viable M. avium subsp. paratuberculosis cells were recovered, resulting in >4.2- to >7.1-fold reductions, depending on the original inoculum concentrations. Inactivation kinetic modeling of 69 quantitative data points yielded an Ea of 305,635 J/mol and an lnk 0 of 107.2, corresponding to a D value of 1.2 s at 72°C and a Z value of 7.7°C. Homogenization did not significantly affect the inactivation. The conclusion can be drawn that HTST pasteurization conditions equal to 15 s at ≥72°C result in a more-than-sevenfold reduction of M. avium subsp. paratuberculosis.

scholarly journals UV Light Inactivation of Mycobacterium avium subsp. paratuberculosis in Milk as Assessed by FASTPlaqueTB Phage Assay and Culture

2007 ◽  
Vol 73 (11) ◽  
pp. 3728-3733 ◽  
Author(s):  
Leslie C. Altic ◽  
Michael T. Rowe ◽  
Irene R. Grant
Keyword(s):  
Mycobacterium Avium ◽  
Uv Light ◽  
Egg Yolk ◽  
Laboratory Scale ◽  
Mycobacterium Avium Subsp ◽  
Uv Treatment ◽  
Static Mixers ◽  
Rapid Enumeration ◽  
Mycobacterium Avium Subsp Paratuberculosis

ABSTRACT UV light inactivation of Mycobacterium avium subsp. paratuberculosis in Middlebrook 7H9 broth and whole and semiskim milk was investigated using a laboratory-scale UV machine that incorporated static mixers within UV-penetrable pipes. UV treatment proved to be less effective in killing M. avium subsp. paratuberculosis suspended in milk (0.5- to 1.0-log10 reduction per 1,000 mJ/ml) than that suspended in Middlebrook 7H9 broth (2.5- to 3.3-log10 reduction per 1,000 mJ/ml). The FASTPlaqueTB phage assay provided more rapid enumeration of surviving M. avium subsp. paratuberculosis (within 24 h) than culture on Herrold's egg yolk medium (6 to 8 weeks). Despite the fact that plaque counts were consistently 1 to 2 log10 lower than colony counts throughout the study, UV inactivation rates for M. avium subsp. paratuberculosis derived using the phage assay and culture results were not significantly different (P = 0.077).

scholarly journals Heat Inactivation of Mycobacterium avium subsp. paratuberculosis in Aseptically Prepared Ground Beef

2011 ◽  
Vol 7 (2) ◽  
Author(s):  
Linda Saucier ◽  
Éveline Plamondon
Keyword(s):  
Heat Treatment ◽  
Mycobacterium Avium ◽  
Ground Beef ◽  
Etiologic Agent ◽  
Mycobacterium Avium Subsp ◽  
Heat Inactivation ◽  
Cooking Methods ◽  
Decimal Reduction Time ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
D Values

Mycobacterium avium subsp. paratuberculosis (Map) is the etiologic agent of Johne’s disease in bovine and other ruminants. Concern for public health was raised when the organism was also suggested to be responsible for Crohn’s disease in humans, although the evidence remains inconclusive. Nonetheless, limiting human exposure to Map is viewed as a proper precautionary measure. Hence, the efficacy of heat treatment to control the organism in milk has been studied but it has not been studied to the same extend in meat. In this study, aseptically prepared ground beef was obtained from beef semimembranosus muscle and inoculated with two stains of Map (ATCC 7080 and gN27) to determine the decimal reduction time (D-value) and temperature sensitivity (z-value) for each strain. A 25 g sample of meat was inoculated with 100 ul of culture to a final concentration of 107 cfu/g. The inoculum was evenly distributed in the meat, which was spread in a thin (2 mm) layer of to maximise heat transfer. Treatments were performed at 55, 60, 65 and 70 °C for times allowing a minimum 5-log reduction. D-values decreased significantly with temperature (P < 0.05) ranging from 80.5 ± 6.1 minutes to 12 ± 1 seconds for both Map strains. When compared to Escherichia coli ATCC 25922 and Enterococcus faecalis ATCC 7080, D-values were significantly lower for E. coli (P < 0.05) whereas E. faecalis was not consistently more resistant than the two Map strains and, therefore, cannot be used as a surrogate strain for Map control with heat treatment. The z-values were not significantly different (P > 0.05) amongst the four strains and ranged from 5.6 ± 0.1 °C to 6.2 ± 0.3 °C. The results suggest that a low concentration of Map could be controlled with conventional cooking methods.

scholarly journals Evaluation of Mycobacterium avium subsp. paratuberculosis faecal culture protocols and media

2006 ◽  
Vol 26 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Paula Ristow ◽  
Marlei Gomes Silva ◽  
Leila de Souza Fonseca ◽  
Walter Lilenbaum
Keyword(s):  
Mycobacterium Avium ◽  
Egg Yolk ◽  
Mycobacterium Avium Subsp ◽  
Faecal Culture ◽  
Faecal Samples ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
Centrifugation Protocol

Paratuberculosis is an important enteritis of ruminants caused by Mycobacterium avium subsp. paratuberculosis (Map). The disease is officially considered exotic in Brazil, but recent serological surveys and the isolation of the agent suggest it may occur in our herds. The aim of this study was to evaluate three different formulations of Herrold's egg yolk agar with mycobactin J (HEYM) and four faecal culture protocols considering their ability for Map growth as well as cost and ease of application. Three formulations of HEYM were inoculated with two suspensions of Map. Spiked faeces and naturally contaminated faecal samples were treated by the four faecal culture protocols. Centrifugation protocol and HEYM recommended by OIE showed the best results on the recovery of Map.

scholarly journals Effect of Egg Yolk on the Detection of Mycobacterium Avium Subsp. Paratuberculosis Using the ESP II Liquid Culture System

2005 ◽  
Vol 17 (6) ◽  
pp. 554-560 ◽  
Author(s):  
N. Beth Harris ◽  
Suelee Robbe-Austerman ◽  
Janet B. Payeur
Keyword(s):  
Mycobacterium Avium ◽  
Culture System ◽  
Liquid Culture ◽  
Egg Yolk ◽  
Mycobacterium Avium Subsp ◽  
Culture Methods ◽  
Solid Media ◽  
Liquid Culture System ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
Time To Detection

Rapid diagnosis of paratuberculosis in infected cattle is important for the successful control of Johne disease within herds. Thus, improving culture methods for Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) will aid in the identification of asymptomatic animals. Egg yolk is a component of the media used for growing M. paratuberculosis, but its requirement as a supplement has not been reported. Using the ESP II liquid culture system, 2 different sources and 5 concentrations (3.3%, 1.6%, 0.8%, 0.4%, and 0%) of egg yolk were analyzed. Egg yolk source did not affect either recovery rate or time to detection, but both parameters were significantly improved when the 3.3% egg yolk concentrations (final volume) were used over media containing no egg yolk. This study also assessed the recovery of M. paratuberculosis from fecal samples that were cultured multiple times using Herrold egg yolk agar (HEY). Specimens containing greater than 70 cfu/g feces could routinely be identified as positive for M. paratuberculosis after only 1 culture attempt, whereas specimens with fewer bacteria were only intermittently positive, even after 5 replicate cultures. Therefore, this study indicates that the sensitivity of the Trek Diagnostic ESP II liquid culture system for M. paratuberculosis is affected by egg yolk concentration and that single culture attempts using HEY solid media may not identify specimens containing low numbers of bacteria.

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