Improved detection of Listeria monocytogenes in soft mould-ripened cheese.

In comparison with standard methods, enrichment in half-Fraser broth for 24 h at 30 degrees C, followed by plating out onto Listeria monocytogenes blood agar (LMBA) and PALCAM medium combined with an additional streak proved to be the most rapid and specific method for the detection of indigenous L. monocytogenes populations from soft mould-ripened cheese. This procedure, with a high sensitivity (93%) and a low detection limit (1-10 cfu 25 g-1), provided negative and presumptive positive results within 2-3 d.

Bactericidal effect of bovine normal and immune serum, colostrum and milk against Helicobacter pylori.

Serum and colostrum but not post-colostral milk from non-immunized Friesian cows was found highly bactericidal for Helicobacter pylori NCTC 11637. This bactericidal activity was destroyed by heating at 56 degrees C for 30 min and restored by the addition of fetal calf serum as a source of complement, indicating that the bacterial effect was probably dependent on an antibody-complement system. Systemic, serial immunization of non-lactating, pregnant cows with H.

Production of hyperimmune bovine colostrum against Campylobacter jejuni.

Serial immunization of dairy cows with Campylobacter jejuni resulted in an enhanced serum antibody response and production of hyperimmune colostrum in all vaccinated animals. An approximate 10-fold decrease in the Camp. jejuni-specific antibody titres in colostrum was observed within 2 d post-partum.