All About Bugs and Food Our Microbial Overlords are wonderful and some are even tasty. But they can bugger up your food business in a heartbeat. The Foodborne FAQs concentrate on bugs relevant to food so you can get them before the bastards get you. There are also other dubious resources - from food alerts to guidance on legislation - all listed under the 'Food' tag. Disclaimer: I'm a microbiologist, not a clinician. These resources mention stuff bugs can do to you or your customers but for medical advice consult a bloody doctor, not the Internet . Especially not this site. Chances are I don't know what I'm talking about anyway and if you have any of the symptoms described here stop twatting about on the Interwebs and see a medic. Refer to the full legal nonsense here , don't run with scissors, stick your tongue into plug sockets, attempt surgery on yourself etc etc. Remember more can impact the survival of bugs in food than the variables listed here so the this is a guide only. If you work in food it's your responsibility to ensure your food is safe, not mine . Using the Rectofossal Resources The RectoBugWiki is a resource primarily aimed at people working in food and so has a lot of geeky, technical stuff. If you want a general rant about any particular organism please contact me and I'll happily write one; our Microbial Overlords are relentlessly fascinating so there's plenty to write about. Various bugs associated with (principally) foodborne illness are listed here; the conditions they like (pH, temperature etc) and how to piss them off (with heat, chemicals etc). I also list those that are notifiable to Local Authority Proper Officers in the UK. Because this is intended to be a resource for people working in food the entries also talk about things like... Water Activity (a w ) Water Activity is (basically) the energy state of water in a system. Microbial growth is dependent on Water Activity, not water content and higher a w substances tend to get more bugs growing on them. Bacteria usually require at least 0.9 and fungi at least 0.7. It's useful in food safety as a critical control point both for HACCP programs and in food design because water migrates from areas of high a w to areas of low a w so if honey (a w ≈ 0.6) is exposed to humid air (a w ≈ 0.7), the honey will absorb water from the air. If smoked salmon (a w ≈ 0.965) is exposed to dry air (a w ≈ 0.5), it will dry out. Especially at weddings. This is important when designing foods for a long shelf life - mixing ingredients with markedly different a w is usually avoided. You can find lost of a w values here . D-Values This relates to how good something is at killing bugs. It is the time taken to kill 90% of a given bug by a certain means, so if a population is reduced by 1 D, 10% of the original organisms remain, 2D 1% remain, 3D 0.1% remain. It's a log scale for those of you with a mathematical bent. Different organisms have different D-values at different temperatures so you might see D 80C = 45s - or that organism is reduced by 90% after exposure to temperatures of 80°C for 45 seconds. Notifiable to Local Authority Some diseases are notifiable (to Local Authority Proper Officers - EHOs) under the Health Protection (Notification) Regulations 2010 due to the danger they present to public health. Note that various syndromes are also notifiable as well as organisms – for example, E. coli O157 is notifiable in its own right but Salmonella isn’t – but ‘food poisoning’ is, as is infectious bloody diarrhoea. (Incidentally, bloody diarrhoea is never a good look - always see a doctor). The full list is: Acute encephalitis, acute infectious hepatitis, acute meningitis, acute poliomyelitis, anthrax, botulism, brucellosis, cholera, diphtheria, enteric fever (typhoid or paratyphoid fever), food poisoning, haemolytic uraemic syndrome (HUS – from some E. coli ), infectious bloody diarrhoea, invasive group A streptococcal disease, Legionnaires’ disease, leprosy, malaria, measles, meningococcal septicaemia, mumps, plague, rabies, rubella, SARS, scarlet fever, smallpox. Hazard Groups Organisms are classified by the WHO and HSE into four Hazard Groups. Some foodborne bugs are in Group 2, in Group 3 we have Salmonella typhi , SARS, VTEC E. coli , Hep B, C and D (the bloodborne ones) and Hep E (turd-to-tongue route and in 10% of sausages). Group 4 is principally stuff like viral haemorrhagic fevers where you bleed to death via every orfice you can think of as well as a few you can't. Don't start any long books. Hazard Group 1: Unlikely to cause human disease. Hazard Group 2: Can cause human disease and may be a hazard to employees; it is unlikely to spread to the community and there is usually effective prophylaxis or treatment available. Hazard Group 3: Can cause severe human disease and may be a serious hazard to employees; it may spread to the community, but there is usually effective prophylaxis or treatment available. Hazard Group 4 : Causes severe human disease and is a serious hazard to employees; it is likely to spread to the community and there is usually no effective prophylaxis or treatment available.

[fusion_builder_container hundred_percent="no" equal_height_columns="no" menu_anchor="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" background_color="" background_image="" background_position="center center" background_repeat="no-repeat" fade="no" background_parallax="none" parallax_speed="0.3" video_mp4="" video_webm="" video_ogv="" video_url="" video_aspect_ratio="16:9" video_loop="yes" video_mute="yes" overlay_color="" video_preview_image="" border_size="" border_color="" border_style="solid" padding_top="" padding_bottom="" padding_left="" padding_right=""][fusion_builder_row][fusion_builder_column type="1_1" layout="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" border_position="all" spacing="yes" background_image="" background_repeat="no-repeat" padding_top="" padding_right="" padding_bottom="" padding_left="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="small-visibility,medium-visibility,large-visibility" center_content="no" last="no" min_height="" hover_type="none" link=""][fusion_text columns="" column_min_width="" column_spacing="" rule_style="default" rule_size="" rule_color="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" animation_type="" animation_direction="left" animation_speed="0.3" animation_offset=""] The species is divided into serotypes on the basis of the O antigen. Cholera is typically associated with O1, but serotype O139 has also been the cause of many cases of cholera in Asia. There are subgroups of O1; classical and El Tor. The classical biovar is responsible for a more severe form of cholera. Growth and Control Growth Temperature : Optimum 37°C. Range 10-43°C. pH : Optimum 7.6. Range 5.0-9.6. The organism can grow relatively quickly under optimum conditions. Atmosphere : Grows with or without oxygen, but growth is optimal under aerobic conditions. Water Activity : Optimum a w 0.984 (0.5% NaCl). Range a w 0.940-0.988 (0.1-4.0% NaCl). Does not require the presence of salt for growth. Survival Temperature : Survives better under refrigeration than at ambient temperatures. Also survives freezing. Viable but Non-Culturable (VNC) Cells : These organisms have been shown to undergo a transition to a VNC state. Inactivation (CCPs and Hurdles) Temperature : D 60C = 2.7 min. D 71C = 0.30 min. pH: Rapidly inactivated at pH values <4.5 at room temperature. Water Activity : Sensitive to drying. Sanitisers/Disinfectants: QACs and hypochlorite are effective disinfectants in the absence of protein. Quaternary ammonium compound quite effective at 50 ppm. Isoproponol used to disinfect hands was effective. Radiation : A dose of 0.5 kGy is optimal for inactivating this organism. D value of 0.11 kGy in frozen prawns. Preservatives : Freshly squeezed lemon juice has been found to inactivate the organism after 5 minutes exposure. Lime juice has also been shown to inhibit growth. Depuration : Not effective for the removal of Vibrio from shellfish. Clinical Incubation: 12 to 72 hours. Symptoms: Cholera: Initially mild diarrhoea progressing to diarrhoea characterised by the production of copious pale grey (“rice water”) stools. Other symptoms include low blood pressure, nausea, abdominal cramps and occasionally fever. The loss of fluids requires rehydration and if this does not happen death by fluid loss can occur. Recovery within 1-6 days in healthy people is normal. Non-O1/O139 : The diarrhoea is milder but may be bloody, and is accompanied by abdominal cramps and fever. Can last 6-7 days. Extraintestinal infections may also occur, e.g. in wounds exposed to contaminated water. Condition: Cholera. Six worldwide pandemics of cholera originating in India are known to have occurred. In the seventh pandemic type O1 El Tor originated from Indonesia. The emergence of type O139 from southern India can be regarded as the eighth pandemic. The hospitalisation rate from cholera has been estimated at 34% and the case fatality rate at 0.6% in the USA. Non-O1/O139: In the developed world most cases are due to non-O1/non-O139 serotypes. Such incidents are normally associated with the consumption of contaminated seafood. Toxins: Cholera toxin and a related adherence factor produced in the intestine are essential components for cholera to occur. A number of other factors are also important. Non-O1/0139 serotypes do not produce these toxins. At Risk Groups: Cholera: Usually between the ages of 2 and 9 years in endemic areas. When people become exposed to new serotypes adults are also susceptible to infection. Non-O1/O139: Diarrhoea may occur in anyone eating contaminated shellfish. Septicaemia can occur in people with liver cirrhosis or who are immunocompromised. Long Term Effects: Prevented by rehydration. Dose: Approximately 100 cells when ingested with food in healthy adults, less in those taking antacids. Treatment: Cholera: Rehydration and electrolyte replacement. Antibiotics shorten the duration of the illness. Non-O1/O139: Usually self-limiting. Antibiotics shorten the duration of the illness. Reservoirs / Sources Human: Believed to be the primary reservoir of the organism. Asymptomatic carriers are known to occur. Animal: Aquatic microscopic animals living in contaminated marine waters become contaminated themselves. O1 strains have been shown to colonise zooplankton at >104 cells per animal. Cholera organisms can be carried by domestic animals, but not for long periods. Non O1/O139 strains are normal inhabitants of the marine environment. Food: Food becomes contaminated from food handlers or contaminated water. The most commonly implicated foods are seafood, including shellfish, fish and crustaceans. Grains, legumes, meat, fruits and vegetables have also acted as vehicles. Fruits and vegetables may be irrigated with contaminated water and consumed raw. Other foods may be contaminated by infected food handlers. Environment: Whether there is a natural aquatic reservoir for O1 and O139 is still under debate, although the weight of evidence suggests that there is. Cholera serotypes have been isolated from Asian, American and Australian waters. Other serotypes are associated with marine, brackish and freshwater aquatic environments. Transmission Routes: By food that has been in contact with contaminated water. Non O1/O139 cases are associated with the consumption of raw oysters. Plague and Pestilence Outbreaks in non endemic countries (mainly USA): Frozen coconut milk (imported from Thailand): (O1) 3 cases, 1 hospitalisation. Control point failure not identified, although insufficient final cooking occurred. Canned palm fruit (imported from El Salvador): (O1 El Tor) 4 infected, 2 symptomatic, both hospitalised. Control point failure: probably incorrect processing of the home canned fruit. Seafood salad (airline meal): 75 infected out of 336 exposed, 10 hospitalised, 1 died. Control point failure: not identified. Raw Oysters: (non-O1) 4 cases. Control point failure: not identified but presumably harvesting contaminated shellfish and/or temperature cock up. Rice: (O1 El Tor) 15 cases. Control point failure: rice washed in contaminated water after cooking, temperature cock up. [/fusion_text][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]

[fusion_builder_container hundred_percent="no" equal_height_columns="no" menu_anchor="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" background_color="" background_image="" background_position="center center" background_repeat="no-repeat" fade="no" background_parallax="none" parallax_speed="0.3" video_mp4="" video_webm="" video_ogv="" video_url="" video_aspect_ratio="16:9" video_loop="yes" video_mute="yes" overlay_color="" video_preview_image="" border_size="" border_color="" border_style="solid" padding_top="" padding_bottom="" padding_left="" padding_right=""][fusion_builder_row][fusion_builder_column type="1_1" layout="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" border_position="all" spacing="yes" background_image="" background_repeat="no-repeat" padding_top="" padding_right="" padding_bottom="" padding_left="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="small-visibility,medium-visibility,large-visibility" center_content="no" last="no" min_height="" hover_type="none" link=""][fusion_text columns="" column_min_width="" column_spacing="" rule_style="default" rule_size="" rule_color="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" animation_type="" animation_direction="left" animation_speed="0.3" animation_offset=""] This genus includes four species; S. dysenteriae, S. flexneri, S. boydii and S. sonnei, which are able to cause bacillary dysentery. They are very similar to Escherichia coli and are serologically cross reactive but have remained separate species for clinical reasons. Growth and Control Growth Very little is known about the growth and survival of the organism in food. S. sonnei is more robust than S. flexneri (data for S. sonnei given). It has been shown to be able to grow on foods (e.g. parsley). Temperature : Minimum 6-7°C, maximum 45-47°C. Will grow on sliced fruits at room temperature. Water Activity : Maximum 5.2% NaCl. pH : Minimum 4.8-5.0 in 3.8-5.2% NaCl, 5.5 in the presence of 300-700 mg/litre NaNO2. Maximum 9.3 in the presence of 5.2% NaCl. Atmosphere : Able to grow in the absence of oxygen. Survival Temperature: In general they survive best at low temperatures (subzero and refrigeration). Can survive storage in butter for more than 100 days at –20°C and 4°C. Can survive storage on soil, cheesevand herbs for 50 days, in orange juice for 1-6 days and in white cheese, cheese curd and salad with mayonnaise from 19-32 days. Persisted for 11-20 days on salads, depending on salad type. Survives heating to 63°C for 2-3 min. Water Activity : In general they survive better in low moisture foods. Some strains can survive 15% NaCl for 1 day. pH : Despite its relatively high minimum pH for growth, Shigella is among the most acid resistant of foodborne pathogens. Some strains can survive exposure to pH 2.5 or 3.0 for 2 hours, and for a few hours to a day in fruit juices of various pH values. Organic acids are more inhibitory than mineral acids. Inactivation (CCPs and Hurdles) Temperature : Rapidly inactivated at temperatures above 65°C. pH : Are inactivated at pH values <4.0 (but can persist for some time, see above). Water Activity : Numbers decline slowly (over days/weeks) at 6% NaCl. Two of 21 isolates survived for 4 days in 10% NaCl. Preservatives : S. flexneri is inhibited by plastic containing 1,500 ppm of triclosan. At pH 5.5 450ppm nitrite was required to inhibit S. flexneri but 700ppm was required to inhibit S. sonnei . Sanitisers/Disinfectants: QACs or chlorine. 90% inactivation was produced by sodium hypochlorite at a concentration 0.5-1.5 mg/litre free chlorine and at 4°C. A 6D reduction was achieved on inoculated parsley with 5.2% acetic acid or 200 ppm free chlorine after 5 minutes exposure at 21°C. Treatment with 7.6% acetic acid or 250 ppm chlorine increased the kill to >7D. Radiation : Sensitive to γ radiation, a dose of 3 kGy results in a 7D kill. D values are of the order of 0.2-0.4 kGy. Clinical Incubation: 12 hours to 4 days. In outbreaks incubation times of up to 36 hours are observed. Symptoms: Abdominal pain, diarrhoea, fatigue, malaise and fever. Mucus and occasionally blood appear in the faeces. The illness may progress to the colonic phase within 1-3 days where the symptoms are intense cramps as well as frequent and painful bowel movements. Lasts for 3 to 14 days. Estimated 13.9% hospitalisation rate, 0.16% case fatality rate. Condition: Bacillary dysentery or shigellosis. Toxins: Toxins are not produced in foods. At Risk Groups: Some groups are more predisposed to infection: children under 6 in day care centres, people in nursing homes or prisons, men who have sex with men. Long Term Effects: Septicaemia sometimes occurs in the immunocompromised host with an associated high fatality rate. May rarely cause haemolytic uraemic syndrome. Dose: The dose required to cause disease is small at 10-100 cells. Treatment: Antibiotic treatment is possible, but is not required in milder cases. Oral replacement of fluids may be required. Antibiotic resistance is common. No effective vaccine exists. Reservoirs / Sources Human: Humans and the higher primates are the reservoir for this organism. The organism can be found in the faeces for weeks after symptoms have ceased. It can survive in human faeces for days if the samples remain moist. Animal: Not carried by animals other than primates. Food: Foods can become contaminated by water or soiled hands. Environment: Water that is contaminated by sewage may act as a vehicle for this organism. Transmission Routes: Person-to-person spread (during convalescence) is important, but in many countries food and waterborne transmission are more significant. Most meals implicated in causing shigellosis comprise cooked food that is served cold and that has been contaminated by a food handler. Food can become contaminated by flies carrying sewage or faeces. Plague and Pestilence Associated with dips, l ettuces, parsley, salads generally. Control measure failures are likely faecal contamination of ready-to-eat food / possible contamination by sick food handler / contaminated water and ice. [/fusion_text][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]

[fusion_builder_container hundred_percent="no" equal_height_columns="no" menu_anchor="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" background_color="" background_image="" background_position="center center" background_repeat="no-repeat" fade="no" background_parallax="none" parallax_speed="0.3" video_mp4="" video_webm="" video_ogv="" video_url="" video_aspect_ratio="16:9" video_loop="yes" video_mute="yes" overlay_color="" video_preview_image="" border_size="" border_color="" border_style="solid" padding_top="" padding_bottom="" padding_left="" padding_right=""][fusion_builder_row][fusion_builder_column type="1_1" layout="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" border_position="all" spacing="yes" background_image="" background_repeat="no-repeat" padding_top="" padding_right="" padding_bottom="" padding_left="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="small-visibility,medium-visibility,large-visibility" center_content="no" last="no" min_height="" hover_type="none" link=""][fusion_alert type="error" accent_color="#808080" background_color="#ffffff" border_size="" icon="" text_align="" text_transform="" dismissable="no" box_shadow="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" animation_type="" animation_direction="left" animation_speed="0.3" animation_offset=""] S. typhi is Hazard Group 3 | Others are Hazard Group 2 | Not notifiable (but bloody diarrhoea is) [/fusion_alert][fusion_text columns="" column_min_width="" column_spacing="" rule_style="default" rule_size="" rule_color="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" animation_type="" animation_direction="left" animation_speed="0.3" animation_offset=""] S. typhi is the causal organism of typhoid (or enteric) fever, representing a more serious form of Salmonella infection than the other salmonellae. Growth and Control The characteristics of this species are essentially those of other non-heat resistant Salmonella . Full details are given on the entry for non-typhoid salmonellae. This is the abridged version appears with S. typhi -specific data given where available. Growth Temperature : Minimum 7°C, growth greatly reduced at <15°C. Maximum 45°C. Optimum 35-37°C. Water Activity : Minimum 0.94, optimum 0.99, maximum >0.99. pH : Minimum 3.8, optimum, 7-7.5, maximum 9.5. The minimum pH is influenced by other factors such as the acid present, and the presence of nitrite etc. Atmosphere : Can grow in the presence or absence of air. Growth under nitrogen is only slightly less than that under air. Grows at 8-11°C in the presence of 20-50% CO 2 . Survival Temperature : Survival can be quite good, for example the organism was viable for 190 days when inoculated onto chocolate biscuits, and for 230 days on sweets. S. typhi can survive for 4 days in shellfish stored at 10-13°C, and in ice for in excess of 90 days. Viable but Non-Culturable (VNC) Cells: This organism is thought to undergo transition to the VNC state in water. Inactivation (CCPs and Hurdles): Water Activity: Inactivated within 1 day when exposed to 30% NaCl. Sanitisers/Disinfectants Treatment of S. Typhi contaminated bean sprouts with 200 mg/l sodium hypochlorite only reduced the count by 1.5 log cycles (i.e. ineffective). Clinical Incubation: 7-28 days (average 14) Symptoms: Fever, malaise, anorexia, spots on trunk. These occur commonly with pea-like diarrhoea or constipation. Patients may become delirious. Recovery is slow, taking from 1 to 8 weeks. Hospitalisation rate estimated at 75%, case fatality rate 0.4%. Condition: Typhoid, or enteric, fever. Toxins: Toxins are not produced in foods. At Risk Groups: In non-endemic areas children between 0-5 years are at the greatest risk. Treatment: Quinolone and cephalosporin antibiotics may be used. Vaccines are available. Reservoirs / Sources Human: Humans are the sole reservoir of this organism. Carriers may harbour the organism in their gall bladders. Animal: Does not infect animals. Food: Foods may become contaminated from food handlers or via the use of contaminated water during processing. Shellfish grown in polluted waters may also accumulate the organism within their tissue. Environment: Water that has been contaminated by human faecal pollution is a transmission route. Survival in seawater for up to 9 days, and in sewage for weeks have been recorded. Survival in groundwater was better than in pond, stream or lake water and this was attributed to less grazing pressure by protozoa. Transmission Routes: Mainly from water or from human carriers. [/fusion_text][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]

[fusion_builder_container hundred_percent="no" equal_height_columns="no" menu_anchor="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" background_color="" background_image="" background_position="center center" background_repeat="no-repeat" fade="no" background_parallax="none" parallax_speed="0.3" video_mp4="" video_webm="" video_ogv="" video_url="" video_aspect_ratio="16:9" video_loop="yes" video_mute="yes" overlay_color="" video_preview_image="" border_size="" border_color="" border_style="solid" padding_top="" padding_bottom="" padding_left="" padding_right=""][fusion_builder_row][fusion_builder_column type="1_1" layout="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" border_position="all" spacing="yes" background_image="" background_repeat="no-repeat" padding_top="" padding_right="" padding_bottom="" padding_left="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="small-visibility,medium-visibility,large-visibility" center_content="no" last="no" min_height="" hover_type="none" link=""][fusion_alert type="error" accent_color="#808080" background_color="#ffffff" border_size="" icon="" text_align="" text_transform="" dismissable="no" box_shadow="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" animation_type="" animation_direction="left" animation_speed="0.3" animation_offset=""] Hazard Group 2 [/fusion_alert][fusion_text columns="" column_min_width="" column_spacing="" rule_style="default" rule_size="" rule_color="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" animation_type="" animation_direction="left" animation_speed="0.3" animation_offset=""] Human noroviruses (NoV) are now the most common cause of outbreaks of epidemic non-bacterial gastroenteritis world-wide. Highly infectious, nightmare to control, 100 billion virus particles per gram of faeces. Previously known as Norwalk-like viruses (NLVs) and small round structured viruses (SRSVs), these viruses belong to the Caliciviridae family and are 26-35 nm non-enveloped single stranded positive-strand RNA viruses. That's really, really small. Each virus is ~30nm wide. Visible light has wavelengths between 300-700nm. Eeek! The noroviruses are probably the single most infectious agents known. Their low infectious dose (1-10 virions), resistance to most chemical agents, prolific faecal shedding in those infected (100x10 9 per gram of stool) - which can continue for two months after symptoms have ceased - all militate towards making this a right little bastard to keep on top of. If it gets into a food business it's a nightmare to get rid of it. Noroviruses are divided into 5 genogroups, GI-V, of which GI, GII and GIV are known to infect humans. Over 25 different human genotypes are now recognised. Since 2002, genotype GII.4 strains have been the most common cause of outbreaks. Recombinant NoV strains have also been identified. Norwalk virus, GI.1, is the prototype strain. Norovirus identification has been difficult prior to development of molecular methods because human noroviruses cannot be cultured, and their wide genetic diversity limits the use of traditional immunology and serotyping assays. Growth and Control Growth Human norovirus has not been grown in vitro and there is still no suitable animal model. This makes it difficult to study. The murine norovirus strain is readily culturable but not ideal. NoV detection is carried out using conventional or – better - real time RT-PCR. This is accurate but seriously expensive and is only likely to be used to investigate a serious outbreak. The illness is self limiting and the clinical diagnosis is accurate enough. There is an ELISA test but it’s pretty crap. Survival It’s reasonably stable on surfaces but not hugely so; a week is a reasonable assumption as you need a rare confluence of circumstances for it to last longer. Inactivation High-level oxidsers or 10,000ppm chlorine. Standard disinfectants ineffective. Temperature The virus retains infectivity after incubation at 60°C for 30 min pasteurisation is not sufficient to eliminate it and resistance is reported to be greater in foods and shellfish. Steaming of bivalve shellfish is unlikely to inactivate NoV – and any cooking process that will would render the shellfish pretty much inedible. 100°C for 5mins will do it. Under refrigeration and freezing conditions the virus remains intact and viable for several years. pH Resists gastric acids at pH 3-4. The virus retained infectivity after exposure to pH 2.7 for 3 hr at room temperature. Believed to be sensitive to pH >9.0 (but unproven cos you can't really test) so the pH in commercial dish wash detergents will render it inactive. Water Activity Based on data for other enteric viruses and virus indicators, it is likely that NoV persist in waters for extended periods (possibly weeks/months). NoV has caused many waterborne outbreaks and are often detected in environmental waters. Drying Infectious NoV has been detected on environmental surfaces, including carpets, for up to 12 days after NoV outbreaks. Preservatives Unknown but likely to be resistant. Sanitisers/Disinfectants Dose-response studies shows that NoV is resistant to inactivation following treatment with free residual chlorine of 0.5 to 1.0 mg/ml - the level of free chlorine consistent with that generally present in a drinking water supply. Clinical Notes Incubation: 10-50 hours (mean 24h) following ingestion of the virus. Symptoms: Vomiting, often projectile, is generally the predominant symptom and is present in > 50% of cases. Stomach cramps, watery non-bloody diarrhoea, abdominal pain, low-grade fever and headache are other common symptoms. The duration of illness is usually between 24-60 hr. Diagnostic criteria are often used in the absence of virological confirmation. Excretion of the virus in stools occurs from onset for up to 8 weeks following infection, with peak excretion rate at 4 days. Noroviruses are frequently discharged in vomit. The disease is generally mild and self-limiting. Hospitalisation is not generally required, but has been reported in some outbreaks. Attack rates are high, generally around 40-60% and sometimes as high as 80%. Condition: Gastroenteritis. Norovirus colonise the proximal region of the small intestine and cause development of mucosal lesions with broadening and shortening of the microvilli. Short-term maladsorption of fats and some sugars has been reported. Abnormal gastric motor function is believed to be the cause of associated nausea and vomiting. The exact mechanism of pathogenesis remains unclear. Susceptibility or resistance to certain strains of HuNoV appears to be associated with human histo-blood group antigens (HBGA) Immunity is generally short lived, and is not sufficiently cross-reactive to protect against different norovirus strains. Dose: Infective dose is estimated at 1-10 particles. Consumption of 1 virus particle may cause infection in 50% of occasions in susceptible people. At Risk Groups: Affects all age groups, but the elderly and the immuno-compromised are particularly susceptible. Long Term Effects: There is no evidence of any long-term sequelae following norovirus infection. Fatalities, which mostly occur in elderly patients, are rare in the developed world. Treatment: Usually none, but fluids may be given to reduce the risk of dehydration. Reservoirs / Sources Human: The only known direct source for human NoV is human faeces or aerosolised vomit. Other indirect sources are shellfish, contaminated foods, water, fomites and the environment. Animal: Bovine, feline, ovine and porcine noroviruses have been identified but there are no reports of cross-species transmission to humans as yet. Overseas, human GII NoV sequences have been identified in swine. Other caliciviruses have been found in various animal species. Food: Contaminated bivalve shellfish, fresh produce (eg. herbs, lettuce, salads), water, ice and manually prepared ready-to-eat foods (including bakery items). Poor hygiene practices by food harvesters, processors and food handlers are a significant source. Environment: Faeces from infected humans may contaminate soil or water. Faecal pollution from sewage discharges, septic tank leachates and boat discharges has caused contamination of shellfish beds, recreational water, irrigation water and drinking water. NoV are believed to survive for long periods in the environment and have been detected in shellfish 8-10 weeks after contamination. Transmission Routes: The faecal/oral route is the established route of transmission. Infection occurs following ingestion of faecally-contaminated food and water. Another important route is person-to-person spread via aerosolised vomit following projectile vomiting. Direct transmission via contaminated surfaces, especially carpets, is also now considered a significant route; These routes contribute to the explosive outbreaks that cannot be attributed to faecal/oral spread alone. They generally occur in semi-closed communities such as rest homes, cruise ships and camps where there is close quarter living and often there may be reduced hygiene levels. There is evidence that asymptomatic food handlers can also cause infection and may excrete high numbers of NoV in their faeces. Plague and Pestilence Because of the relatively high attack rate, large numbers of people are often infected and most cases of disease are outbreak-related. Most foodborne outbreaks are ascribed to cross contamination via a food handler or inadequate cooking of previously contaminated foods. However, any food that becomes contaminated can act as a vehicle. Uncooked or lightly cooked bivalve shellfish such as oysters and mussels present a risk to health if grown in faecally contaminated waters. [/fusion_text][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]

[fusion_builder_container hundred_percent="no" equal_height_columns="no" menu_anchor="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" background_color="" background_image="" background_position="center center" background_repeat="no-repeat" fade="no" background_parallax="none" parallax_speed="0.3" video_mp4="" video_webm="" video_ogv="" video_url="" video_aspect_ratio="16:9" video_loop="yes" video_mute="yes" overlay_color="" video_preview_image="" border_size="" border_color="" border_style="solid" padding_top="" padding_bottom="" padding_left="" padding_right=""][fusion_builder_row][fusion_builder_column type="1_1" layout="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" border_position="all" spacing="yes" background_image="" background_repeat="no-repeat" padding_top="" padding_right="" padding_bottom="" padding_left="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="small-visibility,medium-visibility,large-visibility" center_content="no" last="no" min_height="" hover_type="none" link=""][fusion_text columns="" column_min_width="" column_spacing="" rule_style="default" rule_size="" rule_color="" hide_on_mobile="small-visibility,medium-visibility,large-visibility" class="" id="" animation_type="" animation_direction="left" animation_speed="0.3" animation_offset=""] This is one of two species of the ‘tubercle bacilli’ (the other is M. tuberculosis ) that are able to cause tuberculosis. Unlike M. tuberculosis , M. bovis infects cattle and other animals, and so the disease can be spread to humans via contaminated milk and meat. We gave TB to cows 40-50,000 years ago. From the same genus as leprosy - which diverged from it 40m years ago, Before there were humans to get it... Growth and Control Growth It is a characteristic of the organism that it is very slow growing, and so given the shelf life of foods that it has been associated with, e.g. unpasteurised milk and raw meat, growth in foods is unlikely to be significant. The organism is a microaerophile. Survival Temperature : Survival is better under cool conditions, e.g. survived in cow faeces for 5 months in winter and 2 months in summer. Water Activity: Survives dry conditions well. Inactivation (CCPs and Hurdles): Temperature Inactivated by normal pasteurisation. An inoculum of 105 / ml cells became undetectable after 30 minutes at 63.5oC in whole milk (low temperature, long-time pasteurisation). In meat products the D time at 61°C was 1 min, while at 55°C it was approximately 10 min. Treatment at 65°C for 5 min gives a 5 D kill. Sanitisers/Disinfectants Ortho-phthalaldehyde applied at the minimum effective concentration resulted in a 6 log reduction in numbers in 5 minutes. A study of 14 hospital disinfectants found chlorine dioxide, 0.8% hydrogen peroxide plus 0.06% peroxyacetic acid, glutaraldehydes (2% alkaline and 2% acidic, a phenolic and chlorine (approx. 1,000 ppm) and an iodophor were effective, some quaternary ammonium compounds and 0.13% glutaraldehyde plus 0.44% phenol plus 0.08% phenate were ineffective. On their own chlorhexidine diacetate and cetylpyridinium chloride are relatively ineffective, but their action may be improved in the presence of ethambutol. Radiation : Inactivated by sunlight. Clinical Incubation: In airborne infections and in immunocompetent people the incubation period can be years, while in the immunosupressed it may be months. Cases of the gastrointestinal form can occur after reactivation of infections that must have occurred many years earlier. Symptoms: Fever, chills, weight loss, abdominal pain, diarrhoea or constipation. Other symptoms depend on the organs infected. Symptoms may last for months or years. The organism enters the body via the intestinal tract in foodborne infections, and primary infection is set up in the associated lymph nodes to form ‘tubercles’. The infection is often contained at that point, but it can also spread to other parts of the body to cause illness. The reverse can be true in that pulmonary disease can spread to the intestinal region. Condition: Intestinal tuberculosis or tuberculous enteritis. Toxins: Does not produce toxins. At Risk Groups: Immunosupressed people are especially at risk of either acute infection or reactivation of an infection acquired in the past. In countries where infection is uncontrolled children are at greater risk of infection. Long Term Effects: The course of the disease is long term and may result in death. Dose: The infectious dose for organisms ingested ( as opposed to inhaled ) is probably very high (millions of organisms). Treatment: Multiple antibiotic treatment is required to be administered over protracted periods. This is because the organism may have antibiotic resistance and this will not be apparent for long periods because of the slow growth of the organism. The antibiotics currently used are rifampicin, isoniazid and ethambutol. Infected lymph nodes can be removed. Multiple drug resistant forms have caused outbreaks among AIDS patients that resulted in deaths of all those infected. Reservoirs / Sources Human: Humans are a reservoir of the organism, but human to human infection occurs only rarely. Animal: Cattle and other animals are the main reservoirs of the organism. Food: Meat and milk derived from infected animals may contain the organism. Tubercles are detectable post-mortem in food animals, and infection can also be detected using an immunological test. Environment: Can persist and remain infective in the environment for long periods. Transmission Routes: Can be by respiratory aerosols between humans and animals. To a lesser extent also transmitted by milk and meat derived from infected animals. Apparently not transmitted by the waterborne route. Plague and Pestilence Outbreaks : No recent reports of foodborne outbreaks of M. bovis infection that I can find. The last outbreak attributed to contaminated milk occurred in the UK in 1959. Epidemiological Data : A study in Ireland on disease caused by M. bovis between 1983 and 1992 found that most cases could be attributed to the prior consumption of milk in the pre-pasteurisation era. [/fusion_text][/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]

FAQs

Foodborne Pathogens

Foodborne Pathogens

January 19th, 2020|Pathogens, Food|

Yersinia enterocolitica

Yersinia enterocolitica

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Vibrio parahaemolyticus

Vibrio parahaemolyticus

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Vibrio cholerae

Vibrio cholerae

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Staphylococcus aureus

Staphylococcus aureus

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Shigella

Shigella

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Salmonella typhi

Salmonella typhi

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Salmonella (non-typhoidal)

Salmonella (non-typhoidal)

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Norovirus

Norovirus

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Mycobacterium bovis

Mycobacterium bovis

January 9th, 2020|Pathogens, Bacteria|

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