{"id":189,"date":"2014-07-29T11:19:07","date_gmt":"2014-07-29T11:19:07","guid":{"rendered":"http:\/\/209.151.87.121\/~fomes\/iom\/?p=189"},"modified":"2016-03-16T20:20:58","modified_gmt":"2016-03-16T20:20:58","slug":"hydro-harvest-alfalfa-sprouts","status":"publish","type":"post","link":"https:\/\/www.outbreakmuseum.com\/mobile\/salmonella-mbandaka\/hydro-harvest-alfalfa-sprouts\/","title":{"rendered":"Hydro-Harvest alfalfa sprouts"},"content":{"rendered":"\n<table id=\"tablepress-19\" class=\"tablepress tablepress-id-19\">\n<thead>\n<tr class=\"row-1\">\n\t<th class=\"column-1\"><b>Outbreak:<\/b> Hydro-Harvest alfalfa sprouts<\/th>\n<\/tr>\n<\/thead>\n<tbody class=\"row-striping\">\n<tr class=\"row-2\">\n\t<td class=\"column-1\"><b>Product:<\/b> Alfalfa sprouts<\/td>\n<\/tr>\n<tr class=\"row-3\">\n\t<td class=\"column-1\"><b>Investigation Start Date:<\/b> 02\/01\/1999<\/td>\n<\/tr>\n<tr class=\"row-4\">\n\t<td class=\"column-1\"><b>Location:<\/b> OR, WA, ID<\/td>\n<\/tr>\n<tr class=\"row-5\">\n\t<td class=\"column-1\"><b>Etiology:<\/b> <i>Salmonella<\/i> Mbandaka<\/td>\n<\/tr>\n<tr class=\"row-6\">\n\t<td class=\"column-1\"><b>Earliest known case onset date:<\/b> 01\/09\/1999<\/td>\n<\/tr>\n<tr class=\"row-7\">\n\t<td class=\"column-1\"><b>Latest case onset date:<\/b> 06\/12\/1999<\/td>\n<\/tr>\n<tr class=\"row-8\">\n\t<td class=\"column-1\"><b>Confirmed \/ Presumptive Case Counts:<\/b> 43 \/ 0<\/td>\n<\/tr>\n<tr class=\"row-9\">\n\t<td class=\"column-1\"><b>Positive Samples (Food \/ Environmental):<\/b> 12 \/ 0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-19 from cache -->\n<div id=\"metaslider-id-96\" style=\"width: 100%; margin: 0 auto;\" class=\"ml-slider-3-99-0 metaslider metaslider-flex metaslider-96 ml-slider ms-theme-default\" role=\"region\" aria-label=\"Hydro Sprouts 1999-002\" data-width=\"400\">\n    <div id=\"metaslider_container_96\">\n        <div id=\"metaslider_96\">\n            <ul class='slides'>\n                <li style=\"display: none; width: 100%;\" class=\"slide-1961 ms-image \" aria-roledescription=\"slide\" data-date=\"2015-03-26 22:46:06\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2015\/03\/Alfalfa-Sprout-Picture-2-400x200.jpg\" height=\"200\" width=\"400\" alt=\"Alfalfa seeds from a recalled lot, on exhibit in the museum.\" class=\"slider-96 slide-1961 msDefaultImage\" \/><div class=\"caption-wrap\"><div class=\"caption\">Alfalfa seeds from a recalled lot, on exhibit in the museum.<\/div><\/div><\/li>\n                <li style=\"display: none; width: 100%;\" class=\"slide-1958 ms-image \" aria-roledescription=\"slide\" data-date=\"2015-03-26 22:41:05\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2015\/03\/Alfalfa-Sprout-Picture-400x200.jpg\" height=\"200\" width=\"400\" alt=\"Handful of contaminated alfalfa seeds.\" class=\"slider-96 slide-1958 msDefaultImage\" \/><div class=\"caption-wrap\"><div class=\"caption\">Handful of contaminated alfalfa seeds.<\/div><\/div><\/li>\n                <li style=\"display: none; width: 100%;\" class=\"slide-78 ms-image \" aria-roledescription=\"slide\" data-date=\"2014-07-20 19:17:25\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2014\/07\/1999-002D-e1425547897117-400x200.jpg\" height=\"200\" width=\"400\" alt=\"Reclaimed packaging from recalled alfalfa sprouts on display in the museum.\" class=\"slider-96 slide-78 msDefaultImage\" \/><div class=\"caption-wrap\"><div class=\"caption\">Reclaimed packaging from recalled alfalfa sprouts on display in the museum.<\/div><\/div><\/li>\n                <li style=\"display: none; width: 100%;\" class=\"slide-76 ms-image \" aria-roledescription=\"slide\" data-date=\"2014-07-20 19:17:23\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2014\/07\/1999-002C-400x200.jpg\" height=\"200\" width=\"400\" alt=\"Reclaimed packaging from recalled alfalfa sprouts on display in the museum.\" class=\"slider-96 slide-76 msDefaultImage\" \/><div class=\"caption-wrap\"><div class=\"caption\">Reclaimed packaging from recalled alfalfa sprouts on display in the museum.<\/div><\/div><\/li>\n                <li style=\"display: none; width: 100%;\" class=\"slide-74 ms-image \" aria-roledescription=\"slide\" data-date=\"2014-07-20 19:17:20\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2014\/07\/1999-002A-400x200.jpg\" height=\"200\" width=\"400\" alt=\"Reclaimed packaging from recalled alfalfa sprouts on display in the museum.\" class=\"slider-96 slide-74 msDefaultImage\" \/><div class=\"caption-wrap\"><div class=\"caption\">Reclaimed packaging from recalled alfalfa sprouts on display in the museum.<\/div><\/div><\/li>\n                <li style=\"display: none; width: 100%;\" class=\"slide-1962 ms-image \" aria-roledescription=\"slide\" data-date=\"2015-03-26 22:54:52\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2015\/03\/Seed-Distribution-400x200.jpg\" height=\"200\" width=\"400\" alt=\"Distribution of contaminated seeds that would later be sprouted into outbreak vehicles.\" class=\"slider-96 slide-1962 msDefaultImage\" \/><div class=\"caption-wrap\"><div class=\"caption\">Distribution of contaminated seeds that would later be sprouted into outbreak vehicles.<\/div><\/div><\/li>\n                <li style=\"display: none; width: 100%;\" class=\"slide-1970 ms-image \" aria-roledescription=\"slide\" data-date=\"2015-03-26 23:16:31\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2015\/03\/epi-curve-400x200.jpg\" height=\"200\" width=\"400\" alt=\"Hydro-Harvest Alfalfa Sprout epi-curve\" class=\"slider-96 slide-1970 msDefaultImage\" \/><div class=\"caption-wrap\"><div class=\"caption\">Hydro-Harvest Alfalfa Sprout epi-curve<\/div><\/div><\/li>\n            <\/ul>\n        <\/div>\n        \n    <\/div>\n<\/div>\n\n<table id=\"tablepress-68\" class=\"tablepress tablepress-id-68\">\n<thead>\n<tr class=\"row-1\">\n\t<th class=\"column-1\">Outbreak Summary:<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr class=\"row-2\">\n\t<td class=\"column-1\">The increasing popularity of sprouts as health foods was sharply followed by the epidemiologic discovery that sprouts are prone to transmitting foodborne pathogens like <i>Salmonella<\/i>. This was the largest \"sproutbreak\" of foodborne salmonellosis in Oregon since the multistate and multinational outbreak of <i>Salmonella<\/i> Newport infection in 1996, in which alfalfa sprouts were also implicated as the vehicle of transmission.<br \/>\n<br \/>\n<ul><li>\u2022 <a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC2957971\/\" target=\"_blank\">Outbreak Publication: Emerg Infect Dis. 2003 Apr; 9: 474-9<\/a><\/li><li>\u2022 <a href=\"http:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2015\/03\/EID-handout.pdf\" target=\"_blank\">Investigation summary hand out (PDF)<\/a><\/li><li>\u2022 <a href=\"http:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2015\/03\/CD-Summary-3.2.99.pdf\" target=\"_blank\">\"CD Summary\" Newsletter (PDF)<\/a><\/li><li>\u2022 <a href=\"http:\/\/www.outbreakmuseum.com\/mobile\/wp-content\/uploads\/2015\/03\/sproutQ.pdf\" target=\"_blank\">Outbreak Questionnaire (PDF)<\/a><\/li><\/ul><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-68 from cache -->\n<p style=\"text-align: justify;\">\n<table id=\"tablepress-72\" class=\"tablepress tablepress-id-72\">\n<thead>\n<tr class=\"row-1\">\n\t<th class=\"column-1\">Details:<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr class=\"row-2\">\n\t<td class=\"column-1\"><b>Background<\/b><br \/>\nSince 1995, sprout products (alfalfa, clover, radish, mung bean) have become recognized as common vehicles for enteric pathogens including Salmonella, Escherichia coli O157, and Listeria. Outbreaks have been recognized repeatedly in Europe (notably Scandinavia), North America, and Japan. Most of these outbreaks have been traced to the use of contaminated seed, in which pathogens proliferate during germination. Seed lots are often quite large (\u226518,000 kg) and may be distributed to numerous growers in widely dispersed locations. Outbreaks often manifest as cases scattered across several states or countries, and can persist for months, reflecting the stability of the pathogen on dried seeds.<br \/>\n<br \/>\nThe only completely reliable way to prevent sprout-associated illness is abstinence. In the United States, several state health departments, the FDA, and other agencies have issued statements discouraging raw sprout consumption. Because of the increased risk for severe infection with at least some sprout-associated pathogens (notably Salmonella and Listeria), these warnings are often targeted at immunocompromised individuals. Most persons who become ill in outbreaks are immunocompetent, however.<br \/>\n<br \/>\nMany people enjoy eating sprouts, and many people make a living growing, processing, and distributing these products. In consequence, food scientists and members of the sprout industry have investigated procedures to improve the safety of sprouts. These efforts have concentrated on chemical disinfection of seeds immediately prior to germination.<br \/>\n<br \/>\nLaboratory studies suggest that treatments with sodium hypochlorite or calcium hypochlorite can reduce Salmonella loads on artificially inoculated seeds to undetectable levels. Calcium hypochlorite (at 20,000 ppm) has been strongly recommended, because higher disinfectant levels are achievable without unacceptable reductions in germination rates.<br \/>\n<br \/>\nSome outbreaks provide natural experiments that shed light on the effectiveness of seed disinfection. Oregon Public Health Division epidemiologists investigated one such outbreak in early 1999.<br \/>\n<br \/>\n<b>Methods<\/b><br \/>\nBy law, all Salmonella isolates identified by Oregon laboratories are forwarded to the Public Health Laboratory for serotyping. Similar law or custom obtain in Washington, California, and Idaho. Salmonella Mbandaka is uncommon in Oregon (1988\u201398 mean, 1.5 cases\/year). When 3 Mbandaka isolates were identified within a week in January 1999, it was not difficult to surmise that a common-source outbreak was occurring. Surrounding states and CDC were notified immediately. Initially, reported cases were confined to Oregon.<br \/>\n<br \/>\nPreliminary interviews were conducted with cases or household informants by local health department nurses using standardized case investigation forms. Sprouts\u2014a perennial suspect in geographically dispersed outbreaks of salmonellosis\u2014quickly became a focus of the investigation.<br \/>\n<br \/>\nInvestigators compared exposure histories of the first 10 Oregon cases reported with those of age- and phone prefix-matched controls. We traced sprouts consumed by cases to their origins.<br \/>\n<br \/>\nInformation about later cases was collected by public health agencies in Washington, Idaho, California, and Oregon. Environmental investigations at produce retailers and wholesalers and with sprout growers and seed distributors were conducted by the Oregon and Washington Departments of Agriculture, the California Department of Health and Human Services, and the FDA. Sprouts and seed samples were collected and cultured for Salmonella.<br \/>\n<br \/>\n<b>Results<\/b><br \/>\n<br \/>\nInitial suspicions that commercially distributed alfalfa sprouts were the source (based on demographics, case distribution, and preliminary food histories) were corroborated by case-control study results. Nine of the first 10 cases recalled alfalfa sprout consumption vs. 0\/20 controls (p=0.002). Among cases who had consumed sprouts, 8\/9 reported definite (N=5) or possible (N=3) consumption of Hydro-Harvest sprouts (see Product Traceback figure). No other plausible source was identified.<br \/>\n<br \/>\nOn February 12, press releases were issued announcing a voluntary recall of all Hydro-Harvest sprouts. S. Mbandaka was later cultured from alfalfa sprouts and ungerminated seed collected at the Hydro-Harvest facility. Outbreak-associated cases were eventually identified in four states (see Epidemic Curve): Oregon (N= 40), California (N= 21), Washington (N= 19), and Idaho (N= 5).<br \/>\n<br \/>\nA common outbreak pattern was identified by molecular typing (PFGE and micro-restriction fingerprinting). This pattern differed from those of \u201csporadic\u201d isolates obtained before the outbreak, which were heterogeneous.<br \/>\n<br \/>\nThe implicated seed came from an 18,000-kg lot milled from alfalfa grown in Southern California. By the embargo date, seed from that lot had been distributed to 4 growers in California, 1 in Florida and Hydro-Harvest in Washington (see Seed Distribution figure); one grower had not started to use it. Cases were eventually linked to only 2 of the 5 growers that had sold sprouts from this lot, however: Hydro-Harvest (OR, WA, ID cases) and brand Y in San Diego (CA). Although documentation was incomplete, the 3 sprouters that were not linked to any cases (and who used 41% of the seed) allegedly disinfected with 20,000 ppm calcium hypochlorite or 500 ppm sodium hypochlorite.<br \/>\n<br \/>\n<b>Conclusions<\/b><br \/>\nThis outbreak provided an imperfect natural experiment to assess the efficacy of alfalfa seed disinfection. The observation that\u2014cases were attributable only to the growers who did not disinfect seed\u2013is consistent with, though not proof of, the hypothesis that seed disinfection can reduce the risk of salmonellosis for sprout consumers.<br \/>\n<br \/>\nSeed disinfection procedures could not be verified at any site. No sites, including those who allegedly used the FDA-recommended 20,000 ppm calcium hypochlorite soak, maintained any sort of production log or similar, contemporaneous documentation of disinfection practices. The germination procedures, undertaken by Hydro-Harvest and grower Y, could not be independently verified.<br \/>\n<br \/>\nWhether contamination within seed lot 8119 was uniform could not be assessed, but, S. Mbandaka was recovered from almost every sample tested (both from ready-to-eat sprouts and from seed collected Hydro-Harvest, grower Y, and the originating warehouse).<br \/>\n<br \/>\nThe number of reported cases reflects to some extent publicity about the outbreaks, which differed from state to state. Most importantly, data from other outbreak investigations indicate that even the preferred 20,000 ppm calcium hypochlorite disinfection can be inadequate under at least some circumstances. Seed disinfection may be better than nothing, but it is unclear how much.<br \/>\n<br \/>\n<b>Recommendations<\/b><br \/>\nSprout growers should routinely document seed disinfection methods, and outbreak investigators should carefully review and report these practices. As these data accumulate, we will get a better sense of how effective seed disinfection is.<br \/>\n<br \/>\nSprouts continue to pose a risk for all consumers. Despite episodic publicity, many consumers remain unaware of this risk. Public health advisors should consider ways to increase awareness of this hazard, particularly among high-risk individuals.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-72 from cache --><\/p>\n<p style=\"text-align: justify;\"><a href=\"https:\/\/www.outbreakmuseum.com\/mobile\/exhibits\/\"><strong>Back to Outbreak Exhibits<\/strong><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Back to Outbreak Exhibits<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":true,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19],"tags":[81,77,82,91,80,87,88,79,111,78],"class_list":["post-189","post","type-post","status-publish","format-standard","hentry","category-salmonella-mbandaka","tag-acute-and-communicable-disease-prevention","tag-dr-bill-keene","tag-fomes","tag-hydro-harvest-alfalfa-sprouts","tag-integrated-food-safety-center-of-excellence","tag-international-outbreak-museum","tag-iom","tag-oregon-health-authority","tag-salmonella-mbandaka","tag-tribute"],"_links":{"self":[{"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/posts\/189","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/comments?post=189"}],"version-history":[{"count":6,"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/posts\/189\/revisions"}],"predecessor-version":[{"id":1782,"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/posts\/189\/revisions\/1782"}],"wp:attachment":[{"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/media?parent=189"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/categories?post=189"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.outbreakmuseum.com\/mobile\/wp-json\/wp\/v2\/tags?post=189"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}