PDF(Pubmed)
Abstract：
BACKGROUND: Milk is a common infant food in peri-urban Kenya that can transmit diarrhea-causing enteric pathogens. Little is known about how contamination of milk at point of purchase and household handling of milk-based infant foods contribute to infant exposure to enteric pathogens.
OBJECTIVE: To compare the prevalence and concentrations of bacterial indicator organisms and enteric pathogens in unpackaged, fresh pasteurized, and ultra-high temperature (UHT) treated milk at purchase and assess the influence of the type of milk used to prepare infant food on contamination of this food.
METHODS: Paired samples of purchased milk and infant food prepared with this milk were obtained from 188 households in low-income neighborhoods in Kisumu, Kenya. Samples were cultured on selective media to isolate Salmonella enterica, Shigella spp., Klebsiella aerogenes, Proteus spp., and Escherichia coli, with pathogens validated by PCR. Probability of detection of these bacteria was compared by milk product treatment and packaging method, and between milk at point of purchase vs. food at point of infant consumption.
RESULTS: Unpackaged milk was most contaminated at point of purchase, but bacterial contamination was also present in pasteurized and UHT milk at purchase. Presence of bacteria in UHT and fresh pasteurized milk at purchase predicted presence of the same bacteria type in infant food. Prevalence of bacterial contamination and concentration level for bacterial indicators generally increased between point of purchase and consumption in UHT and fresh pasteurized milk-based food but decreased in unpackaged milk-based food. Prevalence of the four fecal bacteria were similar in infant foods prepared with each type of milk.
CONCLUSIONS: Both pre-market contamination and post-purchase handling influence the likelihood of infants ingesting foods contaminated by diarrheal pathogens.
OBJECTIVE: To compare the prevalence and concentrations of bacterial indicator organisms and enteric pathogens in unpackaged, fresh pasteurized, and ultra-high temperature (UHT) treated milk at purchase and assess the influence of the type of milk used to prepare infant food on contamination of this food.
METHODS: Paired samples of purchased milk and infant food prepared with this milk were obtained from 188 households in low-income neighborhoods in Kisumu, Kenya. Samples were cultured on selective media to isolate Salmonella enterica, Shigella spp., Klebsiella aerogenes, Proteus spp., and Escherichia coli, with pathogens validated by PCR. Probability of detection of these bacteria was compared by milk product treatment and packaging method, and between milk at point of purchase vs. food at point of infant consumption.
RESULTS: Unpackaged milk was most contaminated at point of purchase, but bacterial contamination was also present in pasteurized and UHT milk at purchase. Presence of bacteria in UHT and fresh pasteurized milk at purchase predicted presence of the same bacteria type in infant food. Prevalence of bacterial contamination and concentration level for bacterial indicators generally increased between point of purchase and consumption in UHT and fresh pasteurized milk-based food but decreased in unpackaged milk-based food. Prevalence of the four fecal bacteria were similar in infant foods prepared with each type of milk.
CONCLUSIONS: Both pre-market contamination and post-purchase handling influence the likelihood of infants ingesting foods contaminated by diarrheal pathogens.
摘要：
背景：牛奶是肯尼亚郊区常见的婴儿食品，可传播引起腹泻的肠道病原体。鲜为人知的是，在购买和家庭处理基于牛奶的婴儿食品时，牛奶的污染如何导致婴儿暴露于肠道病原体。
目的：比较未包装的细菌指示生物和肠道病原体的患病率和浓度，新鲜的巴氏杀菌，和购买时的超高温（UHT）处理过的牛奶，并评估用于制备婴儿食品的牛奶类型对该食品污染的影响。
方法：从基苏木低收入社区的188个家庭获得购买的牛奶和用这种牛奶制备的婴儿食品的配对样品，肯尼亚。样品在选择性培养基上培养以分离肠道沙门氏菌，志贺氏菌属。,产气克雷伯菌,变形杆菌。,和大肠杆菌，通过PCR验证的病原体。通过乳制品处理和包装方法比较了这些细菌的检测概率，在购买点和牛奶之间婴儿消费时的食物。
结果：未包装的牛奶在购买时受到的污染最严重，但是购买时巴氏杀菌和UHT牛奶中也存在细菌污染。购买时UHT和新鲜巴氏杀菌牛奶中细菌的存在预测了婴儿食品中相同细菌类型的存在。在UHT和新鲜巴氏杀菌乳基食品的购买点和消费点之间，细菌污染的患病率和细菌指标的浓度水平通常会增加，但在未包装的乳基食品中却有所下降。在用每种牛奶制备的婴儿食品中，四种粪便细菌的患病率相似。
结论：上市前污染和购买后处理都会影响婴儿摄入腹泻病原体污染食品的可能性。
目的：比较未包装的细菌指示生物和肠道病原体的患病率和浓度，新鲜的巴氏杀菌，和购买时的超高温（UHT）处理过的牛奶，并评估用于制备婴儿食品的牛奶类型对该食品污染的影响。
方法：从基苏木低收入社区的188个家庭获得购买的牛奶和用这种牛奶制备的婴儿食品的配对样品，肯尼亚。样品在选择性培养基上培养以分离肠道沙门氏菌，志贺氏菌属。,产气克雷伯菌,变形杆菌。,和大肠杆菌，通过PCR验证的病原体。通过乳制品处理和包装方法比较了这些细菌的检测概率，在购买点和牛奶之间婴儿消费时的食物。
结果：未包装的牛奶在购买时受到的污染最严重，但是购买时巴氏杀菌和UHT牛奶中也存在细菌污染。购买时UHT和新鲜巴氏杀菌牛奶中细菌的存在预测了婴儿食品中相同细菌类型的存在。在UHT和新鲜巴氏杀菌乳基食品的购买点和消费点之间，细菌污染的患病率和细菌指标的浓度水平通常会增加，但在未包装的乳基食品中却有所下降。在用每种牛奶制备的婴儿食品中，四种粪便细菌的患病率相似。
结论：上市前污染和购买后处理都会影响婴儿摄入腹泻病原体污染食品的可能性。
