Meta-analysis to investigate relationships

Irish Journal of Agricultural and Food Research 52: 119–133, 2013

Meta-analysis to investigate relationships between somatic cell count and raw milk composition, Cheddar cheese processing characteristics and cheese composition

U. Geary 1† , N. Lopez-Villalobos 2 , B. O’Brien 1 , D.J. Garrick 2 and L. Shalloo 1 1 Livestock Systems Research Department, Animal and Grassland Research and Innovation Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland 2 Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand

The relationship between elevated somatic cell count (SCC) and raw milk composi- tion, cheese processing and cheese composition, was investigated by meta-analysis using available literature representing 45 scientific articles. With respect to raw milk composition there was a significant positive relationship between SCC and the protein and fat contents and a significant negative relationship between SCC and the lactose content. In relation to cheese processing, there was a significant negative relationship between SCC and recoveries of protein and fat. As SCC increased cheese protein con- tent declined and cheese moisture content increased.

Keywords: cheese; meta-analysis; milk; somatic cell count

Introduction Mastitis is a costly disease within the dairy industry, which manifests itself at both farm and processor level and has been identified as one of the most economi- cally relevant diseases of dairy cattle in Ireland (More et al. 2010). In Ireland, as per EU regulations, the somatic cell

count (SCC) threshold for milk purchas- ers is 400,000 cells/mL and the current national average SCC is 252,000 cells/mL (Teagasc 2012). Geary et al. (2012a) found that Irish farms sustained large losses in profit when bulk milk SCC (BMSCC) increased above 100,000 cells/mL. While a large body of research has been completed

†Corresponding author: Una Geary, Tralee, Co. Kerry, Tel.: +353 86 3584629; Fax: +353 25 42340; E-mail: una.geary@hotmail.com

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