FT2024 Lecture: Food Safety in Fishery Products PDF

 DEPARTMENT OF FOOD TECHNOLOGY, FOOD SAFETY & HEALTH TECHNOLOGY OF FISHERY PRODUCTS Prof. Dr. Ir. Frank Devlieghere – Dr. Lotta Kuuliala – Linyun Chen FOOD SAFETY IN THE FISH PROCESSING INDUSTRY 3 INTRODUCTION 1. Biological health risks...

 DEPARTMENT OF FOOD TECHNOLOGY, FOOD SAFETY & HEALTH TECHNOLOGY OF FISHERY PRODUCTS Prof. Dr. Ir. Frank Devlieghere – Dr. Lotta Kuuliala – Linyun Chen FOOD SAFETY IN THE FISH PROCESSING INDUSTRY 3 INTRODUCTION 1. Biological health risks ‒ Introduction ‒ Microbial health risks ‒ Parasites ‒ Viruses 2. Allergens 3. Chemical health risks ‒ Naturally occurring toxins ‒ Other chemical risks 4. Physical health risks 4 1. BIOLOGICAL HEALTH RISKS: INTRODUCTION 1. BIOLOGICAL HEALTH RISKS: INTRODUCTION 1. BIOLOGICAL HEALTH RISKS: INTRODUCTION 1. BIOLOGICAL HEALTH RISKS: INTRODUCTION  1. BIOLOGICAL HEALTH RISKS: MICROBIAL HEALTH RISKS Table 2: Important organisms responsible for food poisoning associated with fish and shellfish used for consumption 1. BIOLOGICAL HEALTH RISKS: MICROBIAL HEALTH RISKS Bacteria of aquatic origin ̶ Clostridium botulinum type E ̶ Marine Vibrio spp. ̶ V. cholerae ̶ V. parahaemolyticus ̶ V. vulnifcus → Most of the time they occur at low numbers in living fish species: small risk unless they have the oppurtunity to grow ̶ Marine vibrios can occur at high counts: ̶ In shellfish of tropical waters ̶ In fish eating these shellfish of tropical waters ̶ In ‘seafood’ from moderate waters in the summer months ̶ Can cause serious illness (botulism, vibriosis) ̶ Occurs rarely 10 1. BIOLOGICAL HEALTH RISKS: MICROBIAL HEALTH RISKS Bacteria which generally appear in the environment ‒ Listeria monocytogenes ‒ mesophilic C. botulinum (type A and B) → can easily contaminate fish and shellfish products L. monocytogenes appears in many fishery products, especially in cold smoked and minimally treated fish products + L. monocytogenes = psychotrophic 11 1. BIOLOGICAL HEALTH RISKS: MICROBIAL HEALTH RISKS Bacteria of human/animal origin ‒ Shigella spp. ‒ Salmonella spp. ‒ Escherichia coli → Contaminations coming from faecal contaminated water and cross contaminations due to insufficient hygienic measures ‒ Staphylococcus aureus → Can occur especially when manual handlings are involved in the production process Risk for cooked products like shrimps and shellfish, where Staphylococcus can grow because the background bacteria are inactivated by the cooking process 12  1. BIOLOGICAL HEALTH RISKS: MICROBIAL HEALTH RISKS Table 3: The most important bacteriological risks associated with different fish products. 1. BIOLOGICAL HEALTH RISKS: MICROBIAL HEALTH RISKS Figure 1. Overview of pathogens in foodstuffs for 2008, alerted by RASFF (report RASFF 2009; http://ec.europa.eu/food/food/rapidalert/docs/rep ort2009_en.pdf) 1. BIOLOGICAL HEALTH RISKS: MICROBIAL HEALTH RISKS Figure 2. Salmonella spp. in fish and fishery products in Europe in 2008 (report RASFF 2009 ; http://ec.europa.eu/food/food/rapidalert/docs/report 2009_en.pdf) 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.1. Parasites of marine fish: nematodes (roundworms) ‒ Long, cylindrical, non-segmented worms which are sexually dimorphic ‒ Ubiquitous in freshwater, marine, and terrestrial environments ‒ Main zoonotic nematodes in marine fish are members of the family of the Anisakidae: Anisakis, Contraceacum and Pseudoterranova ‒ A. simplex and P. decipiens ‒ ‘Gastric anisakidosis’: serious epigastrical pain as result shortly after consumption of the contaminated fish ‒ Man can ingest these larvae by eating raw insufficiently cooked, salted, brined or smoked fish. Infections frequently occur after eating raw herring, sushi,… 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.1. Parasites of marine fish: nematodes (roundworms) Figure 1: Anisakis spp. in cod. 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.1. Parasites of marine fish: nematodes (roundworms) Figure 2. The life cycle of Anisakis spp. 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.1. Parasites of marine fish: nematodes (roundworms) ‒ P. decipiens (codworm or sealworm) occurring in cod ‒ Life cycle is similar to A. simplex: ‒ P. decipiens has a seal, a sea lion ans a walrus as final host ‒ Important hosts are cod and halibut codworm Encysted larva of Contraceacum spp. 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.2. Parasites in freshwater fish: nematodes ‒ Genus Gnathostoma (gnathostomasis): These larvae occur in freshwater fish muscle as cysts ‒ Final hosts = carnivore mammals like cats, dogs and pigs ‒ Complex lifecycle with a lot of intermediary hosts ‒ Occurs mainly in South-Asia and especially where the food of the intermediary hosts (fish, frogs, ducks, chickens) usually is consumed raw or insufficiently heated (Japan, Thailand, China) ‒ In the South-American countries like Mexico, Peru, Ecuador and Argentinia the reporting of this zoonosis is increasing Gnathostoma Gnathostoma 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.2. Parasites in freshwater fish: cestodes ‒ Segmented flatworms (tapeworms), dimorphic, characterised by a scolex (head), which attaches to the intestinal epithelium of the host, and a long threadlike body (strobila) which is composed out of successive segments (proglottids) posterior to the scolex. ‒ Their life cycle several hosts are involved with as definite hosts fish eating mammals (man in the first place, but also cats, dogs, pigs,...) ‒ Diphyllobothrium latum ‒ 2-15 m long, but few symptoms ‒ Man is responsible for the maintenance of this edema because of the contamination of waters with feces Diphyllobothrium latum 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.2. Parasites in freshwater fish: trematodes ‒ Non-segmented hermaphrodite flatworms characterized by ventral and oral sucking devices ‒ Life cycle with one or more hosts ‒ Widespread over vertebrates as invertebrates ‒ 5 genera of importance: Clonorchis, Opisthorchis, Heterophyes, Haplorchris en Metagonimus 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.3. Prevention and decontamination of marine fish ‒ Avoiding the consumption of raw, insufficiently cooked or insufficiently processed (smoking, salting, brining) fish ‒ Manual removal with a pair of tweezers on top of a lightbox ‒ 53-79% of the infected fish filets are detected ‒ 43%-76% of the infections with Anisakis spp. ‒ In-situ inactivation by ‒ Salt and/or acid ‒ Freezing ‒ Heating 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.3. Prevention and decontamination of marine fish In-situ inactivation by salt and/or acid ‒ Survival in marinades (acetic acid and salt) like e.g. rollmop? ‒ Since these parasites occur in the stomach of mammals, a low pH (from marinade) has not much effect on Anisakis spp.. ‒ Salt has a bigger effect on these parasites ‒ 10 min contact with dry salt ‒ 10 days in a saturated salt solution (22%) ‒ 70 days in a 4% salt solution ‒ In practice: these fish products (e.g. rollmop) are first frozen before they are pickled or marinated In-situ inactivation by freezing ‒ 15 h / -35°C or 7days / -20°C 1. BIOLOGICAL HEALTH RISKS: PARASITES 1.3.3. Prevention and decontamination of marine fish In-situ inactivation by heating ‒ Min of 63°C for 15 seconds or longer ‒ Smoking? ‒ Hot smoking is effective ‒ Cold smoking: temperature to low ‒ In practice: frozen prior to or after smoking Disadvantage of in-situ inactivation ‒ Macroscopical visible parasites are still present: ‒ Consumer ‒ Inactivated larvae can cause allergic reactions 1. BIOLOGICAL HEALTH RISKS: VIRUSES ‒ Viruses = most occurring cause of disease associated with fishery products and shellfish products ‒ Hepatitis A virus is the most serious viral disease associated with seafood products ‒ Most of the viral infection cases are caused by Noroviruses ‒ Viral pathogens are rarely identified as the cause of an illness outbreak because methods for the isolation, cultivation and identification do not or rarely exist (now PCR methods are available) ‒ Transmission = feacal-oral pathway ‒ Faecal contaminated water = source of contamination 2. ALLERGENS ‒ Fish allergy = one of the most common kinds of food allergy ‒ IgE-specific antibodies against specific amino acid sequences which we find in proteins of fish antigens ‒ Occurs a lot in countries where the population consumes a lot of fish, e.g. in Norway 1/1000 people ‒ Fish muscle, however concerns arose on products like fish gelatine ‒ Allergic reaction can be species-specific or not ‒ Allergic reactions caused by cod have been studied a lot. The most important allergen here is a glycoprotein namely gad c1 ‒ Some people are sensitive, some not ‒ Some people are sensitive for one fish species Figure 5. Allergic reaction to food proteins 3. CHEMICAL HEALTH RISKS: 1. NATURALLY OCCURRING TOXINS 3.1.1. Scombrotoxin (histamine)​ One of the most occurring chemical health hazards related to seafood products (tuna, mackerel)​ Scombroid poisoning or histamine poisoning:​ histidine → histamine ​ bacterial decarboxylation ‒ Growth of histamine producing bacteria is encouraged by temperature abuse. Break outs of scombroid poisoning are typically related to a failing cold chain by temperature abuses on boats, in the processing industry, on markets or at home ​ ‒ family of the Enterobacteriaceae or to the genera of Clostridium and Lactobacillus + Photobacterium phosphoreum (psychotolerant) ​ ‒ histamine = heat stable!​ 3. CHEMICAL HEALTH RISKS: 1. NATURALLY OCCURRING TOXINS 3.1.1. Shellfish toxins​​ Shellfish which nourish themselves by filtering the water for algae (e.g. mussles, cockles, oysters) can be toxic during the ‘red tides’ ​ Red tides: Harmful algae are microscopic,single-celled plants that live in the sea. Most species of algae or phytoplankton are not harmful and serve as the energy producers at the base of the food web, without which higher life on this planet would not exist Occasionally, the algae grow very fast or "bloom" and accumulate into dense, visible patches near the surface of the water. "Red Tide" is a common name for such a phenomenon where certain phytoplankton species contain reddish pigments and "bloom" such that the water appears to be coloured red. The algae are usually not harmful; and those species that are harmful may never reach the densities required to discolour the water. Unfortunately, a small number of species produce potent neurotoxins that can be transferred through the food web where they affect and even kill the higher forms of life such as zooplankton, shellfish, fish, birds, marine mammals, and even humans that feed either directly or indirectly on them. 3. CHEMICAL HEALTH RISKS: 1. NATURALLY OCCURRING TOXINS 3.1.1. Shellfish toxins​​ Four human intoxications are related to the consumption of shellfish and the growth of toxic algae:​ ‒ PSP or paralytic shellfish poisoning​ ‒ NSP or neurotoxic shellfish poisoning​ ‒ ASP or amnestic shellfish poisoning​ ‒ DSP or diarrheic shellfish poisoning​ Toxins = non protein molecules​ ‒ Saxitoxins (STX) (PSP) = deadly! ​ ‒ Brevetoxins (NSP)​ ‒ Okadaic acid (DSP)​ ‒ Domoid acid (DSP) Saxitoxin-producing dinoflagellates Alexandrium tamarense saxitoxin 3. CHEMICAL HEALTH RISKS: 1. NATURALLY OCCURRING TOXINS 3.1.3. Ciguatera​​ ‒ Caused by ciguatoxin as result of eating tropical fish​ ‒ Symptoms: nautiousness and neurological deviations (e.g. cold and warm), rarely deadly​ ‒ Source = dinoflagellate Gambierdiscus toxicus which appears on seaweed and serves as food for tropical fish 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.1. Heavy metals ‒ Have always been present in seafood products and are toxic for humans at certain concentrations​ ‒ Natural and antropogenic sources​ ‒ Fish in the open sea: natural contamination​ ‒ Polluted areas: higher concentrations​ ‒ There are no direct proves that heavy metals in fish are a problem for public health Figure 6. Reporting of RASFF related to heavy metals (data RASFF, 2008). 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.1. Heavy metals: MERCURY ‒ Average Hg-concentration:​ ‒ Seawater: 0.1-2 ng Hg/l​ ‒ Coastwater: 0.5-10 ng Hg/l​ ‒ Rivers: till 70 ng Hg/l​ ‒ Mina Mata disease: intoxication by CH3Hg​ ‒ Contaminated fish : 50-250 mg/kg​ ‒ Contaminated shellfish: 50-200 mg/kg​ ‒ Although the very high concentrations of mercury found in local waters, there is no indication of a worldwide contamination. ‒ (CH3)2Hg : lipophylic and accumulates in the fat tissue​ ‒ Higher Hg concentrations in older (fat) fish species​ ‒ Limit = 0.5-1 mg/kg (species dependant) 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.1. Heavy metals: MERCURY Recently measured Hg concentrations < limit​ ‒ Canned tuna: 0.2 mg/kg​ ‒ Fish: < 0.13 mg/kg​ ‒ Shellfish: 0.02-0.05 mg/kg​ Table: Maximum tolerable values (Anon 2001) and threshold values (mg/kg ww) of analysis methods for mercury, lead and cadmium, by processing of 1 gram of sample. Fish Shellfish Squid (cepalopodes) Threshold Mercury 0,5-1 0,5 - 0,0036 Lead 0,2-0,4 0,5-1,0 1,0 0,068 Cadmium 0,05-0,1 0,5-1,0 1,0 0,004 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.1. Heavy metals: LEAD ‒ Natural background concentration in deep waters = 0.4-2 ng/l​ ‒ Surface waters: higher concentrations 5-50 ng/l​ ‒ Pb-concentration in fish decreases with the trophic level and the age​ Trophic level Fish species are classified into levels according to their place in the food chain. These levels are called trophical levels. The lowest organisms in the food chain are categorised in level 1. Fish with a length of 20-50 cm are for example categorised in level 3. And so one could go on according the size of the fishes. 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.1. Heavy metals: LEAD ‒ Lead concentration in fish from the open sea : 2-10 µg/kg​ ‒ In fish from the North Sea and the Baltic Sea: 20-50 µg/kg​ ‒ Especially in fish bones​ ‒ An increased concentration in the fish muscle in areas with agricultural and industrial activities​ ‒ Shellfish have higher concentrations (1 mg/kg) as result of the accumulation in the gastro-intestinal channel and the pancreas​ →gastro-intestinal channel and the pancreas need to be removed before consumption​ ‒ European limits for lead are the following: ​ ‒ fish tissue 0.2 mg/kg ​ ‒ mackerel, sardines, eels and some other species 0.4 mg/kg​ ‒ shellfish 0.5 mg/kg, mussels 1 mg/kg ​ ‒ ungutted cephalopodes 1 mg/kg 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.1. Heavy metals: CADMIUM ‒ Very toxic for living creatures ​ ‒ Very widespread in aquatic environments: bio-accumulation in aquatic organisms​ ‒ Cd-concentration in fish muscle stays low, but high concentrations in organs like liver and kidneys because it accumulates over there. The organs can be heavily contaminated with cadmium and should not be consumed.​ ‒ Concentrations vary according to the fishing areas from 0.5-5 to 10-20 µg/kg but stay under the legally set limits​ ‒ European limits:​ ‒ Fish muscle: 0.05-1 mg/kg (species dependent)​ ‒ Shellfish: 0.5 mg/kg​ ‒ Bivalves and cephalopodes: 1 mg/kg​ 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.2. PBDE (polybromine diphenylethers) and other flame reducers ‒ Brominated flame retardant (BFRs) group​ ‒ Mostly lypophylic ‒ High concentrations (up to 110 µg/kg fresh weight) ​ ‒ Decreasing trend​ ‒ Accumulation especially from BDE-209 is worrisome, because it is unclear whether this compound can be broken down into lower brominated PBDEs ​ polybromine diphenylethers 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.3. Organochlorine pesticides (OCPs) ‒ Especially fat fish, like salmon and eel accumulates in large degree OCPs ​ ‒ Higher concentrations in farmed salmon than in wild salmon (Figure 4)​ ‒ Toxaphene, dieldrin, DDT and derivatives DDE and DDD = dominating contaminants in salmon​ ‒ Toxic effects on liver, the nerve system and liver tumors ‒ Fish = a big source of DDT in the human diet​ ‒ No product limits, but there are exposure limits​ ‒ Decreasing trend in the environment (but some exceptions)​ Green = wild salmon Red = farmed salmon 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.5. Toxaphene ‒ Toxaphene concentrations in North Sea fish are relatively low (1-50 µg/kg fresh weight) ​ ‒ Compared to concentrations in northern waters like in the Norway coast (20-180 g/kg fresh weight) ​ ‒ Strong accumulation in fish, especially fat fish​ ‒ Causes shield gland and liver tumors: potentially carcinogenic​ ‒ Dutch limit for all food products: 0.1 mg/kg product​ 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.6. PCBs, dioxins and dioxin-like PCBs ‒ Group of 209 different congeneres which are persistent organic pollutants with a high toxicity ​ ‒ The biggest threat for the consumption of contaminated fish products goes to the dioxins and the dioxin-like PCBs, because in the consumption of fat fish, concentrations can easily overpass the ‘provisional tolerable weekly intake’ or p-TWI of 14 pg TEQ/ kg bw/week ​ ‒ 2002: new EU limit: 4 pg TEQ/ g for dioxins and fat fish may lead to rejection​ 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.7. PAHs (polyaromatic hydrocarbons)​ ‒ Naphthalene, pyrene, anthracene,… ​ ‒ Partly carcinogenic​ ‒ Shellfish​ ‒ Wild fish < farmed fish < fish food 3. CHEMICAL HEALTH RISKS: 2. OTHER CHEMICAL RISKS 3.2.8. Antibiotic residues​​ ‒ Increasing use in aquaculture ​ ‒ Antibiotics are mainly used for the treatment of bacteriological infections of fish e.g. Aeromonas hydrophila, A. salmonicida, Vibrio salmonicida,… ​ ‒ AB-resistance, allergic reactions, toxic effects and changes in the microflora of the gut​ ‒ Decreasing trend Figure 8. A problem occurred with imported shrimps in 2008 (RASFF, 2009; http://ec.europa.eu/food/food/rapidalert/docs/report20 09_en.pdf)​ 4. PHYSICAL HEALTH RISKS ‒ Fish bones​ ‒ Antennae​ ‒ Shell (shellfish)