Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
(ORCID: https://orcid.org/0000-0001-7047-3127 [M.P.]).
J Food Prot. 2021 Feb 1;84(2):286-290. doi: 10.4315/JFP-20-249.
Growing consumer demand for clean-label "natural" products has encouraged more meat processors to cure meat products with natural sources of nitrate or nitrite such as celery juice powder. One challenge for these producers is to identify safe cooling rates in products cured with celery juice powder where extended cooling could allow growth of pathogens. The Food Safety and Inspection Service of the U.S. Department of Agriculture recently added guidelines for stabilization of meat products cured using naturally occurring nitrites based on control of Clostridium spp. However, a knowledge gap exists for safe cooling rates that prevent the growth of Listeria monocytogenes and Staphylococcus aureus, potential postlethality contaminants, in naturally cured ham. The study was conducted to investigate the temperature profiles of naturally cured hams of typical sizes during refrigerator cooling and to determine the behavior of S. aureus and L. monocytogenes on ham during these cooling periods. Whole hams (14 lb [6,300 g]), half hams (6 lb [2,700 g]), and quarter hams (3 lb [1,400 g]) were slowly cooked in a smokehouse until internal temperatures reached a minimum of 140°F (60°C) and then were immediately transferred into a walk-in cooler (38°F [3.3°C]). Cooling times for hams of all sizes were within the requirements for cured products but not for uncured products. Worst-case scenarios of postprocessing surface contamination were simulated by inoculating small naturally cured ham samples with S. aureus or L. monocytogenes. These inoculated hams were then cooled under controlled conditions of 130 to 45°F (54.4 to 7.2°C) for 720 to 900 min. By the end of cooling, small decreases (0.5 to 0.6 log CFU/g) were found for each inoculum. These findings may help small ham processors evaluating production and quality control methods to determine whether recommended concentrations of natural curing agents used to prevent growth of clostridial pathogens may also prevent growth of other pathogens during meat cooling.
消费者对清洁标签“天然”产品的需求不断增长，促使更多的肉类加工商使用芹菜汁粉等天然来源的硝酸盐或亚硝酸盐来腌制肉类产品。对于这些生产商来说，一个挑战是确定使用芹菜汁粉腌制的产品的安全冷却速度，因为延长冷却时间可能会导致病原体的生长。美国农业部的食品安全检验局最近根据控制梭状芽孢杆菌制定了使用天然产生的亚硝酸盐腌制肉类产品稳定的指南。然而，在天然腌制火腿中，防止李斯特菌和金黄色葡萄球菌生长的安全冷却速度方面仍然存在知识空白，李斯特菌和金黄色葡萄球菌是潜在的致死后污染物。本研究旨在调查典型大小的天然腌制火腿在冰箱冷却过程中的温度曲线，并确定金黄色葡萄球菌和单核细胞增生李斯特菌在这些冷却期间在火腿上的行为。整个火腿（14 磅[6,300 克]）、半火腿（6 磅[2,700 克]）和四分之一火腿（3 磅[1,400 克]）在烟熏房中缓慢烹饪，直到内部温度达到最低 140°F（60°C），然后立即转移到步入式冷却器（38°F[3.3°C]）。所有尺寸火腿的冷却时间都在腌制产品的要求范围内，但不在未腌制产品的要求范围内。通过在小的天然腌制火腿样品上接种金黄色葡萄球菌或单核细胞增生李斯特菌模拟最坏的加工后表面污染情况。然后在 130 到 45°F（54.4 到 7.2°C）的受控条件下对这些接种的火腿进行冷却，持续 720 到 900 分钟。冷却结束时，每个接种物的数量都减少了 0.5 到 0.6 个对数 CFU/g。这些发现可能有助于评估生产和质量控制方法的小型火腿加工商，以确定用于防止梭状芽孢杆菌病原体生长的推荐天然腌制剂浓度是否也可以防止肉类冷却过程中其他病原体的生长。
