Model 926

Proximate composition of the cheeses was determined after approximately 3 d. Moisture content was measured by weight loss using ~3.7 g of grated cheese in a microwave moisture analyzer (model SMART System 5; CEM Corporation, Matthews, NC) at 100% power with an endpoint setting of <0.4 mg of weight change over 2 s. Fat content was measured by a modified Babcock method (Richardson, 1985) . Salt was measured by homogenizing grated cheese with distilled water for 4 min at 260 rpm in a Stomacher. The slurry was filtered through a Whatman #1 filter paper (Whatman International Ltd., Maidstone, UK), and the filtrate was analyzed for sodium chloride using a chloride analyzer (model 926, Corning, Medfield, MA). The S/M content was calculated as salt/(moisture + salt) and expressed as percentage.

The UF retentate and cheese milk were analyzed for TS (Green and Park, 1980), fat (Mojonnier method; AOAC International, 2000) , protein (total percentage N × 6.38, Kjeldahl method; AOAC International, 2000) , CN (AOAC International, 2000) , NPN (AOAC International, 2000) , total Ca (Park, 2000) , and insoluble Ca (ICA) by the acid-base titration method (Lucey et al., 1993; Hassan et al., 2004) . The rennet whey was prepared as described in Lucey et al. (1993) and analyzed for soluble Ca content (Park, 2000) . The cheese composition was analyzed at 2 wk of ripening for moisture (Marshall, 1992) , fat (AOAC International, 2000) , protein by the Kjeldahl method (AOAC International, 2000) , pH by directly inserting a spear tip pH probe (accuCap Capillary Junction pH combination electrode 13-620-133; Fisher Scientific, Itasca, IL) into cheese curd during manufacture or cheese block, salt by the chloride electrode method (model 926, Corning Glass Works, Medfield, MA; Johnson and Olson, 1985) , lactose and lactic acid using HPLC method (Zeppa et Park, 2000) . The ICA content of cheeses were measured at 1 and 4 d, 2 wk, and 1, 3, and 6 mo by the acid-base titration method and calculated as described by Hassan et al. (2004) . All analyses were done in triplicate.

Sodium chloride content was measured using a chloride analyzer (model 926, Corning, Medfield, MA). Grated cheese was mixed with distilled water for 4 min and homogenized at 260 rpm in a Stomacher 400 (Seward, UK). The slurry was filtered through Whatman No. 1 filter paper (Maidstone, UK), and the filtrate was analyzed for salt. Moisture content was determined in triplicate by weight loss using a CEM microwave oven (CEM Corp., Indian Trail, NC) . Fat content was determined using the Babcock method (Marshall, 1992; method 15.8.A) . All proximate analyses were completed 5 d after the cheese was manufactured.