title: Short communication: Influence of preserving factors on detection of β-lactamase in raw bovine milk.
abstract: The refrigeration (4, 8, 24, or 48 d), freezing (1, 7, or 30 h), thawing (25, 40, or 60°C), and usage of preservatives (sodium azide, potassium dichromate, sodium thiocyanate, bronopol, and methanol), of raw bovine milk were investigated for β-lactamase activity. The β-lactamase activity in all samples was assessed by using the test strips, and the samples with the preservatives were further assessed for β-lactamase activity using the cylinder plate method. Results showed that the refrigeration, freezing, and thawing of raw bovine milk samples had no influence on the assay of the β-lactamase activity. The addition of sodium azide or potassium dichromate as a sample preservative failed the test of β-lactamase activity, whereas the addition of sodium thiocyanate, bronopol, or methanol had no influence on the test. In conclusion, sodium azide and potassium dichromate were not suitable preservatives for assessing β-lactamase activity in raw milk when the cylinder plate method was used.
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: Y D
authors: YD
authors: Zhang
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: N
authors: N
authors: Zheng
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: X Y
authors: XY
authors: Qu
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: S L
authors: SL
authors: Li
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: J H
authors: JH
authors: Yang
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: S G
authors: SG
authors: Zhao
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: Yasmeen
authors: Y
authors: Saeed
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors: L
authors: L
authors: Meng
authors: Ministry of Agriculture-Milk Risk Assessment Laboratory, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China. Electronic address: wang-jia-qi@263.net.
authors: J Q
authors: JQ
authors: Wang
mesh_terms: D000818:Animals; D002417:Cattle; D005520:Food Preservatives; D005615:Freezing; D008892:Milk; D012034:Refrigeration; D001618:beta-Lactamases
chemical_list: D005520:Food Preservatives; D001618:beta-Lactamases
keywords: pretreatment; raw milk; β-lactamase