El-Khateib Talaat, Yousef Ahmed E, Ockerman Herbert W
Faculty of Veterinary Medicine, Asuit University, Asuit, Egypt.
Department of Food Science and Technology, The Ohio State University, 2121 Fyffe Road, Columbus, Ohio 43210.
J Food Prot. 1993 Jan;56(1):29-33. doi: 10.4315/0362-028X-56.1.29.
Cubical pieces (1 cm) of aseptically obtained beef muscle were treated with lactic acid (2%), nisin (4 × 10 IU/ml) and pediocin PO2 (a bacteriocin produced by Pediococcus acidilactici PO2; 3.2 × 10 arbitrary units/ml). Treated meat was immersed for 1 min in a cell suspension of a mixture of two strains of Listeria monocytogenes and then stored for 48 h at 4°C. Meat cubes were analyzed immediately after immersion in the cell suspension, then after 1, 24, and 48 h of storage. Count of L. monocytogenes per cube and percentage of attached cells were determined. Data indicated that the antimicrobial agents significantly (p = 0.05) decreased the count of L. monocytogenes during the 48-h storage by 1.7, 1.1, and 0.6 log CFU/6 cm of meat surface for lactic acid, nisin, and pediocin PO2 treatments, respectively. Lactic acid on the meat surface had an immediate and also a delayed listericidal action, but bacteriocins only inhibited L. monocytogenes immediately, and had little or no delayed antilisterial effect. The percentage of Listeria cell attached to the beef muscle significantly (p = 0.05) increased in the presence of lactic acid, but the value did not change significantly or slightly decreased in the presence of nisin and pediocin PO2, respectively.
将无菌获取的牛肉肌肉切成边长为1厘米的正方体小块，用2%的乳酸、4×10 IU/ml的乳酸链球菌素和片球菌素PO2（由嗜酸片球菌PO2产生的一种细菌素；3.2×10任意单位/ml）进行处理。将处理后的肉在两种单核细胞增生李斯特菌菌株的混合细胞悬液中浸泡1分钟，然后在4°C下储存48小时。在浸入细胞悬液后立即对肉块进行分析，然后在储存1小时、24小时和48小时后进行分析。测定每块肉中单核细胞增生李斯特菌的数量以及附着细胞的百分比。数据表明，抗菌剂在48小时的储存期间显著（p = 0.05）降低了单核细胞增生李斯特菌的数量，乳酸、乳酸链球菌素和片球菌素PO2处理分别使每6平方厘米肉表面的单核细胞增生李斯特菌数量减少1.7、1.1和0.6 log CFU。肉表面的乳酸具有即时和延迟的杀李斯特菌作用，但细菌素仅能立即抑制单核细胞增生李斯特菌，几乎没有或没有延迟的抗李斯特菌作用。在乳酸存在下，附着在牛肉肌肉上的李斯特菌细胞百分比显著（p = 0.05）增加，但在乳酸链球菌素和片球菌素PO2存在下，该值分别没有显著变化或略有下降。
