The influence of incubation on the formation of volatile bacterial metabolites in mastitis milk.
The possibility to detect mastitis-causing pathogens based on their volatile metabolites was previously studied. In that study, the mastitis samples were incubated overnight. To minimize the total analysis time, no incubation, or a short incubation, would be preferred. We therefore investigated the effect of the incubation time on the formation of volatile metabolites in mastitis samples. A selection of 6 volatile metabolites with the highest impact on the prediction model for identifying the mastitis-causing pathogen, was compared at different incubation times between 0 and 24 h. Identification of the pathogens was not possible without incubation. The minimum incubation time for detection of most of the 6 metabolites was 4 to 8 h. Although a longer incubation time increased the differences between pathogens, after 8 h all metabolites could be detected and the pathogens could be differentiated. Eight hours was therefore selected as the optimal incubation time. This optimal incubation time was evaluated with a set of 25 mastitis samples, of which 88% were correctly classified after 8 h of incubation. The total analysis time for this method is therefore considerably shorter than current microbiological culturing.
Hettinga
K A
KA
Dairy Science and Technology group, Wageningen University and Research Centre, 6700EV Wageningen, the Netherlands. kasper.hettinga@wur.nl
van Valenberg
H J F
HJ
Lam
T J G M
TJ
van Hooijdonk
A C M
AC
D000818:Animals; D001419:Bacteria / Q000302:isolation & purification* / Q000378:metabolism*; D002417:Cattle; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000302:isolation & purification / Q000378:metabolism; D005260:Female; D008414:Mastitis, Bovine / Q000382:microbiology*; D008892:Milk / Q000737:chemistry / Q000382:microbiology*; D016571:Neural Networks, Computer; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000378:metabolism; D013291:Streptococcus / Q000302:isolation & purification / Q000378:metabolism; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000032:analysis / Q000378:metabolism*
D055549:Volatile Organic Compounds