Abstract
Cow milk is a primary source of trace elements iodine and selenium. Deficiency of iodine and selenium in the diet can result in various endemic diseases. Furthermore, literature has stressed that dietary intakes of selenium and iodine are insufficient in Ireland and the UK. In addition, it is established that pathogenic and spoilage bacteria are present in milk. However, milk also contains beneficial bacteria including probiotic bacteria important for the development of dairy products.The aims of this project were to characterise Northern Ireland milk by using combined element and microbial analysis, and to link these to Northern Irish environment and husbandry, to enable the milk industry to proactively use this information to maximize the promotion of Northern Ireland milk and dairy products, to address opportunities arising from Global Food Security Challenges and or Food safety risk management.
Three different farm- based sampling campaigns were completed. Samples of milk, soil, silage and grass have been collected from farms across Northern Ireland and analysed. Study one was completed in 2016, samples were collected from 71 farms across Northern Ireland during winter. Study two was completed in 2017, samples were collected from 48 farms across Northern Ireland during summer. Study three investigated farming practice; samples of milk, grass and silage were collected every two months, over one year, from farms across Northern Ireland that contrasted in having year-round housing, or not. For these 3 studies, iodine and selenium levels were quantified using inductively couple plasma-mass spectroscopy (ICP-MS). In addition, microbial analysis was completed using a combination of culture dependant and culture- independent approached to determine and compare the microbial diversity in milk samples.
This research found that iodine and selenium display very strong relationships in the environment. However, despite the strong environmental relationships there appears to be
disconnect between the environment and milk iodine concentrations, as milk iodine and selenium concentrations did not correlate with any of the environmental parameters (p>0.05). Season had an important determining effect on the iodine and selenium concentrations in milk, with higher concentrations evident during winter months in comparison to summer months.
| Date of Award | Dec 2019 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Sponsors | Department of Agriculture, Environment and Rural Affairs |
| Supervisor | Andy Meharg (Supervisor) & Caroline Meharg (Supervisor) |