{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/45244"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/45244","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Concentration of sulfamethazine in spray dried milk","abstract":"A study was conducted to investigate the effect ofspray drying on concentration of sulfamethazine (SMZ) in fluid milk dried to powder «10% moisture). Antibiotic-free skim and whole (homogenized) milk were spiked at 5, 10, 50 and 100 ppb sulfamethazine levels, pasteurized and stored at 4°C till further processed. All samples were spray dried at an inlet temperature of 180 ± 2°C and outlet temperature of 100 ± 2°C and stored at -20°C until analyzed. Sulfamethazine concentration was determined quantitatively by HPLC, a microbial receptor assay (Charm-II®) and an ELISA assay (LacTek®) and qualitatively by an ELISA method (Cite®) in milk samples before and after spray drying. Dry milk samples were reconstituted (10% w/w) for all analyses. statistical determination of significant differences (p = 0.05) between fluid and dry milk samples and whole and skim milk sample~was completed by paired t-tests. Sulfamethazine concentrations increased 81.4% and 84.1% in skim and whole milk respectively at 100 ppb spiked level but were lower than expected increase of 88-91% based on their total solids for whole and skim milk as obtained by modified FDA HPLC method. At lower levels of 5 and 10 ppb, the HPLC method was not sensitive enough to provide usable data. Increase in sulfamethazine concentration from fluid to dry milk was also determined by· Charm-II® and LacTek® techniques. Poor recoveries and variability in data were evident due to binding of sulfamethazine to undetermined milk components as a result of processing and storage also due to break-down of sulfamethazine (mp = 176°C) at 1S00C during spray drying. Sulfamethazine 163 ppb by LacTek® and 94.6 ppb by Charm-II® (at a spiked level of 10 ppb fluid milk) was successfully removed from dried milk after 120 min using supercritical CO₂ (pressure = 5500 psi, 50 0 C","abstract_html":"A study was conducted to investigate the effect ofspray drying on concentration of sulfamethazine (SMZ) in fluid milk dried to powder «10% moisture). Antibiotic-free skim and whole (homogenized) milk were spiked at 5, 10, 50 and 100 ppb sulfamethazine levels, pasteurized and stored at 4°C till further processed. All samples were spray dried at an inlet temperature of 180 ± 2°C and outlet temperature of 100 ± 2°C and stored at -20°C until analyzed. Sulfamethazine concentration was determined quantitatively by HPLC, a microbial receptor assay (Charm-II®) and an ELISA assay (LacTek®) and qualitatively by an ELISA method (Cite®) in milk samples before and after spray drying. Dry milk samples were reconstituted (10% w/w) for all analyses. statistical determination of significant differences (p = 0.05) between fluid and dry milk samples and whole and skim milk sample~was completed by paired t-tests. Sulfamethazine concentrations increased 81.4% and 84.1% in skim and whole milk respectively at 100 ppb spiked level but were lower than expected increase of 88-91% based on their total solids for whole and skim milk as obtained by modified FDA HPLC method. At lower levels of 5 and 10 ppb, the HPLC method was not sensitive enough to provide usable data. Increase in sulfamethazine concentration from fluid to dry milk was also determined by· Charm-II® and LacTek® techniques. Poor recoveries and variability in data were evident due to binding of sulfamethazine to undetermined milk components as a result of processing and storage also due to break-down of sulfamethazine (mp = 176°C) at 1S00C during spray drying. Sulfamethazine 163 ppb by LacTek® and 94.6 ppb by Charm-II® (at a spiked level of 10 ppb fluid milk) was successfully removed from dried milk after 120 min using supercritical CO₂ (pressure = 5500 psi, 50 0 C","abstract_has_math":false,"creators":["Malik, Shahana"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Food Science and Technology","degree_department":"Food Science and Technology","school":null,"contributors":[],"advisors":[],"committee_chairs":["Duncan, Susan E."],"committee_members":["Bishop, J. Russell","Taylor, Larry T."],"year":1991,"date_issued":"1991","date_published":"1991","updated_at":"2026-07-22T22:18:55Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-10222009-125009"],"render_values":[{"text":"etd-10222009-125009","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/45244","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Duncan, Susan E."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Bishop, J. 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Antibiotic-free skim and whole (homogenized) milk were spiked at 5, 10, 50 and 100 ppb sulfamethazine levels, pasteurized and stored at 4°C till further processed. All samples were spray dried at an inlet temperature of 180 ± 2°C and outlet temperature of 100 ± 2°C and stored at -20°C until analyzed. Sulfamethazine concentration was determined quantitatively by HPLC, a microbial receptor assay (Charm-II®) and an ELISA assay (LacTek®) and qualitatively by an ELISA method (Cite®) in milk samples before and after spray drying. Dry milk samples were reconstituted (10% w/w) for all analyses. statistical determination of significant differences (p = 0.05) between fluid and dry milk samples and whole and skim milk sample~was completed by paired t-tests. Sulfamethazine concentrations increased 81.4% and 84.1% in skim and whole milk respectively at 100 ppb spiked level but were lower than expected increase of 88-91% based on their total solids for whole and skim milk as obtained by modified FDA HPLC method. At lower levels of 5 and 10 ppb, the HPLC method was not sensitive enough to provide usable data. Increase in sulfamethazine concentration from fluid to dry milk was also determined by· Charm-II® and LacTek® techniques. Poor recoveries and variability in data were evident due to binding of sulfamethazine to undetermined milk components as a result of processing and storage also due to break-down of sulfamethazine (mp = 176°C) at 1S00C during spray drying. Sulfamethazine 163 ppb by LacTek® and 94.6 ppb by Charm-II® (at a spiked level of 10 ppb fluid milk) was successfully removed from dried milk after 120 min using supercritical CO₂ (pressure = 5500 psi, 50 0 C"]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["BTD"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Concentration of sulfamethazine in spray dried milk"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Duncan, Susan E."],"dc:contributor.committeemember":["Bishop, J. Russell","Taylor, Larry T."],"dc:contributor.department":["Food Science and Technology"],"dc:creator":["Malik, Shahana"],"dc:date.accessioned":["2014-03-14T21:47:59Z"],"dc:date.available":["2014-03-14T21:47:59Z","2009-10-22"],"dc:date.issued":["1991"],"dc:description.abstract":["A study was conducted to investigate the effect ofspray drying on concentration of sulfamethazine (SMZ) in fluid milk dried to powder «10% moisture). Antibiotic-free skim and whole (homogenized) milk were spiked at 5, 10, 50 and 100 ppb sulfamethazine levels, pasteurized and stored at 4°C till further processed. All samples were spray dried at an inlet temperature of 180 ± 2°C and outlet temperature of 100 ± 2°C and stored at -20°C until analyzed. Sulfamethazine concentration was determined quantitatively by HPLC, a microbial receptor assay (Charm-II®) and an ELISA assay (LacTek®) and qualitatively by an ELISA method (Cite®) in milk samples before and after spray drying. Dry milk samples were reconstituted (10% w/w) for all analyses. statistical determination of significant differences (p = 0.05) between fluid and dry milk samples and whole and skim milk sample~was completed by paired t-tests. Sulfamethazine concentrations increased 81.4% and 84.1% in skim and whole milk respectively at 100 ppb spiked level but were lower than expected increase of 88-91% based on their total solids for whole and skim milk as obtained by modified FDA HPLC method. At lower levels of 5 and 10 ppb, the HPLC method was not sensitive enough to provide usable data. Increase in sulfamethazine concentration from fluid to dry milk was also determined by· Charm-II® and LacTek® techniques. Poor recoveries and variability in data were evident due to binding of sulfamethazine to undetermined milk components as a result of processing and storage also due to break-down of sulfamethazine (mp = 176°C) at 1S00C during spray drying. Sulfamethazine 163 ppb by LacTek® and 94.6 ppb by Charm-II® (at a spiked level of 10 ppb fluid milk) was successfully removed from dried milk after 120 min using supercritical CO₂ (pressure = 5500 psi, 50 0 C"],"dc:description.degree":["Master of Science"],"dc:format.medium":["BTD"],"dc:format.mimetype":["application/pdf"],"dc:identifier.other":["etd-10222009-125009"],"dc:identifier.uri":["http://hdl.handle.net/10919/45244"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Concentration of sulfamethazine in spray dried milk"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Food Science and Technology"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:55Z"}