Departamento de Investigación y Posgrado en Alimentos, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas s/n. Col. Las Campanas 76010, Querétaro, Querétaro, México.
(ORCID: https://orcid.org/0000-0002-3313-5433 [M.H.I.]).
J Food Prot. 2021 Jan 1;84(1):99-105. doi: 10.4315/JFP-19-595.
Consumption of seeds has increased in recent years due to their high nutrient content. However, Salmonella outbreaks associated with the consumption of low-water-activity food items have also increased, although these food items do not support microbial growth. The main goal of this study was to quantify microbial indicators and to determine the prevalence and content of Salmonella in chia, amaranth, and sesame seeds obtained from Mexican retail outlets. In addition, the behavior of this pathogen on seeds was evaluated. One hundred samples of each product (chia, amaranth, and sesame seeds) were collected from Queretaro City markets. Aerobic plate count, coliforms, and Escherichia coli bacteria were quantified, and the presence and number of Salmonella pathogens were also determined. Chia, amaranth, and sesame seeds (1 kg each) were inoculated with a cocktail of five Salmonella strains (∼6 log CFU mL-1) and stored at ambient temperature, and then populations of Salmonella were quantified. The median aerobic plate count contents in chia, amaranth, and sesame seeds were 2.1, 2.4, and 3.8 log CFU g-1, respectively, and the content of coliforms on the seeds ranged from 0.48 to 0.56 log most probable number (MPN) per g. E. coli was present at low concentrations in the three types of seeds. Salmonella was detected in chia (31%), amaranth (15%), and sesame (12%) seeds, and the population ranged from 0.48 to 0.56 log MPN g-1. Salmonella levels decreased through 240 days of storage, showing inactivation rates of 0.017, 0.011, and 0.016 log CFU h-1 in chia, amaranth, and sesame seeds, respectively. The high prevalence of Salmonella in the seeds highlights potential risks for consumers, particularly given that seeds are generally consumed without treatments guaranteeing pathogen inactivation.
由于种子的高营养含量，近年来其消费有所增加。然而，与食用低水分活度食品相关的沙门氏菌爆发也有所增加，尽管这些食品并不支持微生物生长。本研究的主要目的是量化微生物指标，并确定从墨西哥零售店购买的奇亚籽、苋菜和芝麻中沙门氏菌的流行率和含量。此外，还评估了这种病原体在种子上的行为。从克雷塔罗市的市场上采集了每种产品（奇亚籽、苋菜和芝麻）的 100 个样本。定量了需氧平板计数、大肠菌群和大肠杆菌细菌，并确定了沙门氏菌病原体的存在和数量。将五种沙门氏菌菌株（约 6 log CFU mL-1）的混合物接种到 1 公斤奇亚籽、苋菜和芝麻中，并在环境温度下储存，然后定量沙门氏菌的种群。奇亚籽、苋菜和芝麻种子的需氧平板计数含量中位数分别为 2.1、2.4 和 3.8 log CFU g-1，种子上大肠菌群的含量范围为每克 0.48 至 0.56 个最可能数（MPN）。三种种子中均存在低浓度的大肠杆菌。在奇亚籽（31%）、苋菜（15%）和芝麻（12%）种子中检测到沙门氏菌，种群数量范围为 0.48 至 0.56 log MPN g-1。沙门氏菌水平在 240 天的储存过程中下降，奇亚籽、苋菜和芝麻种子的失活率分别为 0.017、0.011 和 0.016 log CFU h-1。种子中沙门氏菌的高流行率突出了消费者面临的潜在风险，特别是考虑到种子通常未经处理就被食用，无法保证病原体失活。
