Fresh Produce Related Outbreaks - Essay Example

Microbiology of Fresh Produce Related Outbreaks In terms of the number of casualties and the economic effects, one thing, that has been a big concern to public health, is illness caused or transmitted through food. According to the Centre for Disease Control and Prevention (CDC), cases reported indicate that about 48 million people acquire foodborne illness in the United States every year. Of these, an estimated 3000 people succumb to death while there are about 128,000 admitted to hospital beds on a yearly basis. In Canada, the estimated number foodborne illnesses that occur yearly ranges between 11 million and 13million. Over the past two decades, there has been a rapid increase in outbreaks of foodborne illnesses and other cases that are due to fresh produce. Estimates show that produce accounts for about 20 million illnesses in the US, which is about 24% (Farber, Crichton, and Snyder, 2014). That leads to an estimated cost of $38.6 Billion every year. In the 1970s, produce rarely earned recognition as a major vessel of outbreaks and cases of illnesses in the US. It only accounted for 0.7% of the outbreaks and 1% of cases of the illnesses. However, due to increased evidence, the numbers increased in the 1990s and produce now accounted for about 6% and 12%. Between 1990 and 2003, there was a further increase and the estimates in the US were now 16% of outbreaks and 30% of total cases. Some estimates also indicate that between the year 1990 and 2005 produce accounted for about 13% of all outbreaks of illnesses and 21% of the cases in the US. Using a more recent interval from 1998 to 2007, the estimates show that produce accounts for about 14.8% of the outbreaks and 22.8% of all cases of foodborne illnesses that occurred in the US. Produce, which includes fruits, vegetables and salads contributed to about 111, 228 and 345 illness outbreaks respectively (Farber, Crichton, and Snyder, 2014). Of the illnesses reported, vegetables and salads contributed the largest number of illnesses. That was about 11,200 illnesses caused by each of the two categories. According to an analysis of data concerning outbreaks in the US for the period between 1988 and 2008, on average, the illness outbreaks caused by produce amount to between 6.3 and 13.2 per year. In recent times, leafy greens contribute to a third of the outbreaks. Reports indicate that in Canada, produce accounted for 15 outbreaks for the period between 1991 and 2000. The cases due to foodborne illness in that period were about 1360 (Farber, Crichton, and Snyder, 2014). There are several microorganisms, which have been, on several occasions, associated with outbreaks of illnesses related to the consumption of fresh produce. Such microorganisms may be viruses, protozoa or bacteria. The viruses include hepatitis A virus and norovirus while the protozoa include Cyclospora cayetanensis and Cryptosporidium parvum. The bacteria associated with such outbreaks include Aeromonas (A.) hydrophila, Salmonella (S) spp., Bacillus (B.) cereus, E. coli O157:H7, Clostridium (Cl.) spp., Listeria (L.) monocytogenes, Shigella (Sh.) spp., Yersinia (Y.) enterocolitica, Campylobacter (C.) spp. and Vibrio (V.) cholera (Farber, Crichton, and Snyder, 2014). Notably, Salmonella and E. coli O157: H7 have been consistent causes of large outbreaks of foodborne illness that have a link to fresh produce. Due to better epidemiological methods and detection in the US, there have been more connections of viruses to causes of illness outbreaks due to produce. Between 1973 and 1997, 20% of the outbreaks had a link to viruses while it went up to about 51% in the period between 1998 and 2007. In the latter period, Salmonella and E. coli O157:H7 accounted for 7% and 17% of the outbreaks due to produce respectively. A review of food poisoning outbreaks due to single items of fresh produce in the US for the period between 1990 and 2004 indicate that the most common agents in terms of bacteria were E. coli O157:H7 and S. enterica. Of the outbreaks due to leafy vegetables, seed sprouts and fruits, S. enterica accounted for about 30%, 60%, and 76% respectively. E. coli O157:H7,however, accounted for 48%, 40%, and 19% respectively. More results indicate that Salmonella spp and E. coli O157:H7 strains were a major cause of outbreaks due to contaminated fresh produce (Farber, Crichton, and Snyder, 2014). Between 1998 and 2007, the outbreaks associated with fresh produce were more than those due to poultry, pork, seafood, eggs or beef in the US. During this period, the average number of cases was 39.1 per outbreak. The number went up to 47.8 in during the period between 1990 and 2005. Estimates also estimate that produce was responsible for about 43%, 62% and 65% of norovirus, parasitic and other viral outbreaks in the US (Farber, Crichton, and Snyder, 2014). Again, the estimates indicate a link of produce to 35% and 43% of illnesses and Shigella outbreaks respectively. Salmonella outbreaks and cases account for 27% and 37% while of E. coli O157:H7 outbreaks and cases account for 39% and 54% of all the incidents with a food connection. According to past estimates, for the period 1982 to 2002, 21% of E. coli O157:H7 outbreaks in the US are attributable to fresh produce. Among all the vessels that cause E. coli illness outbreaks, fresh produce was the second most common for the period 2000 to 2004. Observations show a link between E. coli O157 outbreaks and lettuce, alfalfa sprouts, radish, apple cider and other mixed salads. In 1996, Japan recorded over 12000 cases of E. coli O157:H7 with 12 deaths. That is the largest outbreak on record and was due to consumption of raw radish sprouts. Another outbreak occurred in the US and Canada in 2006. The cause for the outbreak was spinach, and it led to 199 E. coli O157:H7 cases and three deaths reported over 26 states. There was hospitalization in 51% of the cases while 16% experienced acute renal failure. In the year 2010, five US states experienced an outbreak infections of human E. coli O145. The main cause of the outbreak was shredded romaine lettuce and led to 33 cases, 26 of which were confirmed while 7 were probable cases. In May 2011, Germany experienced a large outbreak due to E. coliO104:H4. That came about because of contaminated fenugreek seed sprouts, and it affected visitors from about 14 European countries and seven from North America. Of the seven North Americans affected by the outbreak, one died. Out of the 3911 cases 47 resulted to death while there was development of hemolytic uremic syndrome (HUS) in 777 patients. France experienced a similar outbreak a month later in Bordeaux, which caused 16 illnesses. The cause for the Bordeaux outbreak was fenugreek sprouts that contained E. coli O104:H4contamination. The sprouts germinated locally, but the origin of the seeds from which they were germinated, which was two years before the outbreak, was Egypt. There was still another lethal outbreak in 2011. The cause for the outbreak was cantaloupe. The cantaloupe was contaminated with L.monocytogenes, and its distribution reached 28 states in the US. It led to 146 illnesses, 30 deaths (20.5%) and one miscarriage. Although most foodborne illness due to Salmonella usually has a connection to poultry, recent cases indicate that fresh produce is also a major vessel (Farber, Crichton, and Snyder, 2014). In 2008, there was a big outbreak of salmonellosis in 43 states within the US and Canada. The outbreak caused 1442 illnesses that all had a link to the consumption of hot peppers. There was also another outbreak of salmonellosis in late 2010 and early 2011. That affected 26 US states and had 140 illnesses. The cause for the outbreak was alfalfa or spicy sprouts from a multistate restaurant chain. Foodborne illness outbreaks consistently occur courtesy of fresh produce such as cantaloupes, lettuce, tomatoes, seed sprouts and Green salad. There are several pathogen-produce combinations that frequently occur in outbreaks. Such combinations include E. coli O157:H7 and leafy green vegetables, Salmonella and cantaloupes, sprouts or tomatoes, hepatitis A with green onions, and Cyclospora, and raspberries. To reduce the increasing effect of contaminated produce on foodborne illness, a deeper understanding of reasons for such increase is important. That is because such understanding will lead to the development of measures to combat such effects. Sources of Pathogens that Contaminate Fresh Produce Whereas spoilage bacteria, molds, and yeasts predominantly occur on vegetables and raw fruits, there is frequent isolation of pathogenic bacteria, viruses, and parasites. Such contamination can be either pre or post-harvest. There are several pre-harvest sources of contamination. They include soil, dust, irrigation water used, fecal matter, reconstituted fungicides, and insecticides, inadequately composted manure, insects, animals and human handling. On the other hand, post-harvest contamination may be due to human handling, harvesting equipment, processing equipment, rinsing water, insects, ice, dust, transport containers and transport vehicles (Farber, Crichton, and Snyder, 2014). Soil is the most natural environment for a variety of human pathogens. Such pathogens include Cl. botulinum and Cl. perfringens, L. monocytogenes and Aeromonas and B. cereus. However, the addition of animal waste to soil greatly boosts the existence of these pathogens. Reports show that the survival period for Salmonella and E. coli O157:H7 in soil is about 7 to 25 weeks. That depends on the type of soil, its moisture level, temperature and the source of contamination. As shown by reports, L. monocytogenes, E. coli O157, Salmonella and C. jejuni can survive in soil up to a maximum of between 45 and 100days. Evidence from accumulated work shows that such pathogens have a longer survival period under some conditions such as moist clay-based soils, lower temperatures, and manure. Another major factor as pertains microbial safety of fresh produce would be the conditions of the area in which they grow. There is a higher risk of contamination by enteric pathogens in fields containing animal manure. That is because they are able to survive in soils for a long time stretching to several months or years. Fecal matter may naturally comprise of between 102 and 105 CFU/g E. coli whereas its Salmonella spp. composition is between 102 and 107 CFU/g. Slurry has between 10 and 104 CFU/g E. coli and Yersinia spp. while manure has between 102 and 107 CFU/g Salmonella spp. The main sources of E. coliO157:H7 and Salmonella are sewage and manure from ruminants. The gastrointestinal microflora of pigs, cattle, and poultry is the main source of C. jejuni while nature, in terms of soil and decaying matter form the main source of L. monocytogenes. L. monocytogenes commonly contaminates vegetables, especially root crops (Farber, Crichton, and Snyder, 2014). Foodborne pathogens can survive for long in animal manure and at cool temperatures. Studies have that the survival of E. coli O157:H7 can be over 70days at 5°C in bovine water. However, it can only last 49days at 22 or 30°C. Studies on the survival of Campylobacter, E. coli O157:H7, Salmonella and Listeria in 35,000L tanks of fresh livestock showed that the pathogens’ survival was in the following order; Campylobacter< Listeria Read More