Hew Carrie M, Hajmeer Maha N, Farver Thomas B, Riemann Hans P, Glover James M, Cliver Dean O
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, California 95616, USA.
J Food Prot. 2006 May;69(5):1087-95. doi: 10.4315/0362-028x-69.5.1087.
This study addressed health risks from ethnic sausages produced on a small scale, without inspection, in California and elsewhere. Mexican-style chorizo, a raw pork sausage that is not cured, fermented, or smoked, was contaminated experimentally in the batter with Escherichia coli O157:H7, Listeria monocytogenes, or Salmonella serotypes and stuffed into natural casings. Formulations were based on a market survey in California. Physical parameters that were controlled were pH, water activity (a(w)), and storage temperature. The pH was adjusted with vinegar, stabilizing at 5.0 within 24 h. Initial a(w) levels adjusted with salt were 0.97, 0.95, 0.93, 0.90, and 0.85; levels declined with time because of evaporation. Pathogen numbers declined with storage up to 7 days, with few brief exceptions. Main effects and interactions of constant temperature and pH with declining a(w) on survival of the pathogens were determined. Maximum death rates occurred at higher a(w) for E. coli O157:H7 and Salmonella than for L. monocytogenes. Salt used to adjust a(w) affected palatability. Spices (black pepper, chili pepper, chili powder, cumin, garlic, guajillo pepper, oregano, and paprika) comprised another, potentially significant aspect of the sausage formulation. Some (notably black pepper and cumin) carried an indigenous microflora that contributed significantly to the microbial load of the sausage batter. Only undiluted fresh and powdered garlic exhibited a significant antimicrobial effect on the pathogens. Although each of the tested formulations caused death of the inoculated pathogens, none of the death rates was sufficiently rapid to ensure safety within the probable shelf life of the product.
本研究探讨了加利福尼亚州及其他地区未经检验的小规模生产的民族特色香肠所带来的健康风险。墨西哥风味的西班牙辣香肠是一种未经腌制、发酵或烟熏的生猪肉香肠，在面糊中通过实验接种了大肠杆菌O157:H7、单核细胞增生李斯特菌或沙门氏菌血清型，然后装入天然肠衣。配方是基于在加利福尼亚州的市场调查制定的。控制的物理参数包括pH值、水分活度（a(w)）和储存温度。用醋调节pH值，24小时内稳定在5.0。用盐调节的初始a(w)水平分别为0.97、0.95、0.93、0.90和0.85；由于蒸发，水平随时间下降。病原体数量在储存7天内下降，仅有少数短暂例外。确定了恒温、pH值以及a(w)下降对病原体存活的主要影响和相互作用。大肠杆菌O157:H7和沙门氏菌在较高a(w)时的最大死亡率高于单核细胞增生李斯特菌。用于调节a(w)的盐影响了适口性。香料（黑胡椒、辣椒、辣椒粉、孜然、大蒜、瓜希略辣椒、牛至和辣椒粉）是香肠配方中另一个潜在的重要方面。一些香料（特别是黑胡椒和孜然）携带的本土微生物群对香肠面糊的微生物负荷有显著贡献。只有未稀释的新鲜大蒜和大蒜粉对病原体表现出显著的抗菌作用。尽管每种测试配方都导致接种的病原体死亡，但没有一种死亡率足够快，能确保产品在可能的保质期内安全。
