Heat-resistant spores under UHT treatment [in milk]
1996
Meier, J. | Rademacher, B. | Walenta, W. | Kessler, H.G. (Technical Univ. of Munich, Weihenstephan (Germany). Dairy and Food Research Centre)
Reports on surviving sporeforming bacteria in UHT milk have been accumulating for a few years. Investigations of UHT milk samples yielded, after mesophilic incubation (30 degrees, 2 weeks) according to the demands of the EU-Regulation 92/46, a growth of sporeforming bacteria up to a maximum of 10 exp 5/ml. UHT milk containing such heat-resistant spores is consumable but, according to statute law, not acceptable. Milk of three dairies which had previously experienced problems with surviving mesophilic spores were submitted to heating experiments. In fact, the comparison with earlier measurements of milk from dairies which have not experienced this problem showed a distinct enhanced heat resistance that requires raised heating temperatures and/or heating times for complete inactivation. In such cases, especially under indirect UHT, lactulose values higher than 400 mg/kg are to be expected. Extensive investigations in Germany, France, Great Britain, Italy and elsewhere revealed that more than 50 percent of indirect UHT milk surpasses the lactulose limit of 400 mg/kg.
显示更多 [+] 显示较少 [-]