U.S. Department of Agriculture, Agricultural Research Service, Food and Feed Safety Research Unit, 2881 F&B Road, College Station, Texas 77845.
Veterinary Integrative Biosciences, Texas A&M University, 3201 Russell Long Boulevard, College Station, Texas 77845.
J Food Prot. 2022 Jul 1;85(7):1008-1016. doi: 10.4315/JFP-22-049.
Pork head meat may harbor Salmonella and contaminate other carcass by-products during harvest and fabrication. A large pork processing plant in the United States was sampled bimonthly for 11 months to determine the concentration, prevalence, seasonality, serotype diversity, and antimicrobial susceptibility of Salmonella enterica isolated from cheek meat and head trim of swine carcasses. Each collection consisted of 25 samples on two consecutive days in the morning and afternoon shifts, for a total of 100 cheek meat and 100 head trim samples each month. Tissues were cultured for Salmonella by using restrictive media and enrichment techniques, and a subset of isolates was serotyped, analyzed for antimicrobial susceptibility, and genome sequenced. Salmonella postenrichment prevalence did not differ (P = 0.20) between cheek meat (63%) and head trim (66%). Postenrichment prevalence differed (P < 0.05) by month (January, 94%; March, 80%; May, 54%; July, 59%; September, 47%; and November, 55%) and by processing shift (morning, 68%; afternoon, 62%). The subset (n = 618) of isolates selected for serotyping yielded 21 distinct serotypes: Typhimurium (49%), Infantis (10%), Heidelberg (8%), I 4,[5],12:i:- (8%), and 17 other types (≤5%). In total, 407 multidrug-resistant (MDR; resistance to three or more antibiotic classes) isolates were identified. There were 120 isolates that exhibited the penta-resistant ACSSuT phenotype. In addition, 113 isolates exhibited decreased susceptibility to ciprofloxacin (MIC ≥ 0.12 μg/mL). Resistance genes blaCARB, blaSHV, blaTEM, aac(6')-Ib-cr,qnrB, sul2, and dfrA were expressed in numerous MDR Salmonella isolates. The data herein suggest that pork products from the head, compared with data reported for carcasses, may have a relatively high prevalence of Salmonella with diverse serotypes and MDR.
猪头肉在收获和加工过程中可能携带沙门氏菌，并污染其他胴体副产物。美国的一家大型猪肉加工厂每月进行两次采样，共进行了 11 个月，以确定从猪胴体的面颊肉和头颈部采集的肠沙门氏菌的浓度、流行率、季节性、血清型多样性和对 25 种抗生素的敏感性。每个采集都包括连续两天上午和下午的两班各 25 个样本，每月共采集 100 份面颊肉和 100 份头颈部样本。采用限制培养基和富集技术对沙门氏菌进行组织培养，对部分分离株进行血清分型、分析对 25 种抗生素的敏感性，并对基因组进行测序。增菌后的沙门氏菌流行率在面颊肉（63%）和头颈部（66%）之间无差异（P=0.20）。增菌后流行率因月份而异（1 月 94%、3 月 80%、5 月 54%、7 月 59%、9 月 47%和 11 月 55%）和加工班次（上午 68%、下午 62%）而异。选择用于血清分型的分离株亚组（n=618）产生了 21 种不同的血清型：鼠伤寒沙门氏菌（49%）、婴儿沙门氏菌（10%）、海德堡沙门氏菌（8%）、I 4,[5],12:i:-（8%）和 17 种其他类型（≤5%）。总共鉴定出 407 株多药耐药（MDR；对三种或三种以上抗生素类别耐药）分离株。有 120 株分离株表现出 penta-resistant ACSSuT 表型。此外，113 株分离株对环丙沙星的敏感性降低（MIC≥0.12μg/ml）。blaCARB、blaSHV、blaTEM、aac(6')-Ib-cr、qnrB、sul2 和 dfrA 耐药基因在许多 MDR 沙门氏菌分离株中表达。与 carcasses 相比，本研究数据表明，猪头部位的猪肉产品可能具有相对较高的沙门氏菌流行率、多种血清型和 MDR。
