Introduction

Map has been linked to human Crohn's disease. During the last ten years, there has been progress in the research of the relationship between this microorganism and Crohn's disease, which has been focused on food products as the transmission pathway. The way in which Map is transmitted in not fully understood yet, but some lines of evidence suggest that humans can get infected through contaminated milk. Some authors showed that when Map is present in milk, the bacteria is able to resist the pasteurization conditions. The objective of this study is investigate if viable Map is present in commercial pasteurized milk

Materials and Methods

Seventy commercial milk (18 pasteurized, 30 ultra-pasteurized (138°C 30 sec), and 22 ultra-pasteurized high temperature (150°C 15 sec) were collected over seven months. Milk samples (50 ml) were centrifuged at 2,500 x g for 30 minutes and the pellet was suspended in 0.75% of hexadecylpyridinium. The samples were centrifuged again and the pellet inoculated on Herrold's egg yolk medium with mycobactin and sodium piruvate. PCR based on amplification of the IS900 sequence was used to detect Map from these milks. The isolates were analyzed by RFLP.

Results

Map was isolated from 2 (2.86%) of 70 pasteurized milk. One from pasteurized and other from ultra-pasteurized milk. Both positive culture samples were also positive with IS900-PCR. The RFLP of these isolates were pattern A, one of the most prevalent Map type in Argentina.

Conclusion

This study provides evidence that viable Map is present in pasteurized milk. This result has become very important since human exposure to Map is a potential risk for Crohn´s disease.