Detection of Viable Mycobacterium avium subsp. paratuberculosis in Retail Pasteurized Whole Milk by Two Culture Methods and PCR

Abstract

Cattle with Johne's disease can shed live Mycobacterium avium subsp. paratuberculosis (MAP) in their milk, and MAP can survive under simulated commercial pasteurization conditions. In several studies conducted in the United Kingdom and Canada, MAP DNA has been detected in retail pasteurized milk samples; however, in one study in the United Kingdom viable MAP was identified in commercially pasteurized milk. A double-blind study involving two laboratories was undertaken to evaluate retail pasteurized whole milk in the United States. Marshfield Clinic Laboratories used solid culture medium (Herrold's egg yolk agar slants with mycobactin J and amphotericin B, nalidixic acid, and vancomycin), and TREK Diagnostic Systems, Research and Development used liquid culture medium (ESP culture system). Cultures at both laboratories were eonfirmed by PCR. A total of 702 pints of retail whole milk were purchased in three of the top five milk-producing states (233 from California, 234 from Minnesota, and 235 from Wisconsin) over a 12-month period and were tested for the presence of viable MAP. The criteria used for identifying samples as positive for viable MAP were similar to those followed by most laboratories (positive culture with PCR confirmation). The combined data from the two laboratories revealed the presence of viable MAP in 2.8% of the retail whole milk pints tested. Although the number of samples containing viable MAP was similar among states (P > 0.05), there was a seasonal effect on the presence of viable MAP in retail milk (P = 0.05). More MAP-positive samples were identified during the third quarter of the year (July through September). Of the 22 brands of retail milk tested, 12 (55%) yielded at least one sample positive for viable MAP.

Mycobacterium avium subsp. paratuberculosis in powdered infant milk: paratuberculosis in cattle - the public health problem to be solved

“…Confirmed MAP isolates were cultured from 1.8% of the commercially pasteurized milk samples in the U.K. (Grant et al, 2002). Similar data were published from the U.S.A. (Ellingson et al, 2005). In the U.K. study the 10 culture-positive pasteurized milk samples were from just 8 (3.3%) of the 241 dairy processing establishments that participated in the survey (Grant et al, 2002).…”

Modeling the Effect of Direct and Indirect Contamination of On-Farm Bulk Tank Milk with Mycobacterium avium subsp. paratuberculosis

“…Our estimated MAP concentration in raw milk was 10 4 CFU/mL in the worst case; therefore heat inactivation should be effective. Still, MAP isolation in milk sampled at retail stores has been reported (Ellingson et al, 2005;Stephan et al, 2007). It has recently been reported that spore-forming MAP may survive heat treatments of 70°C (Lamont et al, 2012), which could explain the occasional MAP survival after heat treatments.…”

“…Most milk produced on cattle farms in dairy-producing countries is pasteurized, which may reduce MAP in milk by 4-7 log 10 (Cerf et al, 2007). However, MAP bacteria and DNA have been found in dairy products in retail stores, indicating survival of MAP during the processing (Ellingson et al, 2005;Stephan et al, 2007). The increasing implications of the role of MAP in Crohn's disease suggest that minimizing contamination of milk at the farm level may be advisable.…”

Assessment ofDietziasubsp.C79793-74for treatment of cattle with evidence of paratuberculosis

“…2,[4][5][6][7][8][9][10][11][12] As Johne disease has become an increasingly worldwide problem, due in part to the absence of preventive vaccine/drug or curative treatments, 13 including the partially protective, MAP subunit vaccine, 14 awareness as to what role, if any, animals play in the transmission of MAP to humans is being raised. [15][16][17][18][19][20][21] This concern arises from the apparent specific association of MAP with Crohn disease, even though a role (etiology agent?) remains to be established.…”