| dc.description.abstract | We hypothesized that at low doses (<2.0kGy) electron beam processing, a non-thermal food pasteurization technology, would be effective at inactivating the microbial pathogens potentially present in raw milk without compromising or degrading its composition, nutritional value, and aromatic profiles. The log10 reductions of background microbial populations and inoculated pathogens (Coxiella burnetii, Campylobacter jejuni, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus) in raw milk was determined. The possible reduction in infection risks associated with these pathogens was also quantified using β-Poisson and exponential risk assessment models. After eBeam processing, milk was analyzed to determine potential losses in the concentrations of lactose, vitamin B2, vitamin B12, and calcium. Casein and whey proteins were analyzed for signs of breakdown with SDSPAGE. Lipid oxidation was measured using the TBARS method, and GC-MS olfactory analysis was used to determine changes in the aromatic compound profile. When exposed to 2.0 kGy, the numbers of aerobic and anaerobic microbial populations (8.1 x 10^4 and 2.9 x 10^3 CFU/mL respectively) in raw milk were reduced to below detectable limits representing >3.5 and ~2.5 log10-reductions for aerobic and anaerobic microorganisms, respectively. At 2.0 kGy eBeam dose, significant reductions in predicted lethality of raw milk associated pathogens can be observed (between 13-logs and 28-logs). QMRA illustrated the significant reductions in infection risks eBeam pasteurization of raw milk can achieve through pathogen elimination. Without eBeam pasteurization, ingestion of raw milk containing ~40 CFU/mL L. monocytogenes or ~10^3 CFU/mL C. jejuni or E. coli O157:H7 would result in ~8/10, ~8/10, or ~10/10 infections for these pathogens, respectively. However, if raw milk is eBeam pasteurized at 2.0 kGy, the infection risks from consumption would be reduced to ~<1/9.735 million persons. Except for vitamin B2 (which showed a 31.57% loss), none of the other targeted nutrients were affected at 2.0 kGy. There was no indication of lipid oxidation after eBeam processing. However, by day 7 of refrigerated storage, there was a 350% increase in lipid oxidation in the 2.0 kGy samples as compared to the non-irradiated samples. There were only minimal changes in the aromatic compound profiles after eBeam processing | en |
