Dar seafood ppp standard
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- Bu səhifədəki naviqasiya:
- Effects of processing on levels of hazards in cephalopod molluscs
- Crustacea
- Effects of processing on levels of hazards in crustacea
- Lobsters
- Other crustaceans – redclaw crayfish, marron, yabbie and scampi
Cephalopod molluscsCephalopod molluscs have not been implicated as the vehicle in any outbreaks of food-borne illness in Australia during the period 1995 to June 2002 (Appendix 2 for outbreak data) and were not the subject of any FSANZ-coordinated food recalls in the period 1990–2003. Under the Imported Foods Inspection Scheme testing regime, failures were recorded for imported squid products for high mercury concentrations (one failure, at 1.6 mg/kg, in 98 tests) and the standard plate count (two failures in 19 tests) in the period 1998 to June 2003 (inclusive). No failures were recorded for enteric pathogens, Vibrios or shellfish toxins. Factors affecting the presence of potential hazards along the production and processing supply chain for cephalopod molluscs have been considered at the point of harvest, during processing and at subsequent points in the distribution chain. The hazards are broadly summarised in Table 1.3 and discussed at greater length below. Effects of processing on levels of hazards in cephalopod molluscsOctopus, squid and other cephalopods eat a diet of crustacea, fish and other molluscs. The marine environments from which they are harvested are largely free of significant levels of pollution. Endogenous hazards which may be present at point of harvest are broadly similar to those associated with other molluscan species, although there is no evidence for the accumulation of algal biotoxins in the cephalopods. Conversely, squid is known to be an intermediate host for anisakid parasites [2]. Squid and octopus are usually landed live and sold as chilled or frozen product. Squid are imported in many forms, including whole dried; dried and shredded; dried shredded and smoked; canned; frozen hoods; and frozen rings. Octopus are imported dried, salted, smoked and marinated. In Australia, processing of octopus is minimal, involving washing, brining to evert the octopus, removal of teeth and organs, and subsequent chilling or freezing. Squid, calamari and cuttlefish are similarly minimally processed. The internal organs, skeleton and the skin are removed, the product washed, and cleaned tubes and/or bodies are stored chilled or frozen. Post-harvest handling introduces the risk of contamination by pathogenic micro-organisms, and handling and transport introduce the possibility for outgrowth of bacterial pathogens if temperature is not adequately controlled. Table 1.3: Summary of potential hazards along the cephalopod mollusc supply chain
CrustaceaCrustacea, specifically prawns and crayfish, have been implicated in six outbreaks of food-borne illness in Australia in the period 1995 to June 2002 (Appendix 1). The hazards involved have included hepatitis A virus, S. typhi, S. typhimurium, V. cholerae and C. perfringens. In the case of the two outbreaks of perfringens food poisoning from consumption of curried prawns, the likely source of contamination is the spices used in the dish [3], as C. perfringens is not usually considered a seafood-associated pathogen. The failures recorded for imported crustacea in Imported Foods Inspection Program testing data for the period January 1998 to June 2003 (inclusive) are listed in Table 1.4. In the period 1990–2003, FSANZ coordinated three food recalls for crustacea (for unspecified microbiological contamination, Salmonella and excess sulphur dioxide). Further evidence of a public health risk due to crustacea was found in the recent cooked prawns survey coordinated by FSANZ [4]. In this survey, 380 samples of chilled or frozen cooked prawn were tested for the Standard Plate Count and Listeria monocytogenes. The retail temperature of the chilled prawns was also determined. The survey covered peeled and unpeeled, imported and domestic prawns. The contamination rate of Listeria monocytogenes in cooked prawns was low (3%) and the levels of those detected were also low (<50 cfu/g). The Standard Plate Counts ranged from negligible (<103 cfu/g) to high (>107 cfu/g), and the temperatures of cooked prawns varied from frozen to 12.8C. However, there was no correlation between high Standard Plate Counts and high temperatures. Results from the survey were used in the semi qualitative risk assessment FSANZ conducted for ‘Listeria monocytogenes in cooked crustacea’ [5]. Table 1.4: Significant imported foods testing failures for crustacea, 1998–2003*
* No failures were recorded for crustacean imports tested for coliforms, mercury, cadmium, inorganic arsenic, total arsenic, other metals and heavy metals, organophosphates, organochlorines or PCBs. Effects of processing on levels of hazards in crustaceaPrawnsPrawns are produced through both wildcatch and aquaculture production methods. Prawns are bottom-feeding, opportunistic omnivores, and will consume a wide variety of foods depending on availability. They are subject to a range of hazards through their environment, both chemical and microbiological. Further hazards can also be introduced during subsequent processing, handling, transport and storage stages (Table 1.5). Wildcatch: A range of prawn species are commercially harvested as wildcatch in Australia, from both estuarine and marine environments. Catch is obtained from a wide range of locations, covering much of the Australian coastline. The primary method of catch is demersal otter trawling. Free-living prawns may encounter a range of hazards in their environment, both chemical and microbiological. Significant chemical hazards originating from the environment include the metals arsenic and mercury. Both of these are recognised as human toxins, and their presence in crustacea is regulated under the Code. Cadmium has also been identified as a food safety hazard associated particularly with endeavour prawns (Metapenaeus spp.) harvested in certain geographical regions [6], but it was concluded that no maximum level standard was necessary in the Code. Other chemical residues may be present in wild-catch crustacea due to industrial pollution and agricultural run-off. This will be a greater risk in estuarine prawns than those caught in open marine waters. Table 1.5: Potential food safety hazards along the crustacean supply chain
Prawns are also potentially exposed to a range of indigenous microbial contaminants from the water environment, including A. hydrophila, V. parahaemolyticus, V. vulnificus, V. cholerae, Salmonella spp. and L. monocytogenes [3,7]. Vibrios are known to utilise the chitinous exoskeleton of crustacea as points of attachment and to metabolise it as a carbon/energy source [3,8]. V. parahaemolyticus, V. vulnificus and V. cholerae are considered part of the indigenous microflora of estuarine prawns [9]. V. cholerae O1 and O139 and Salmonella spp. derived from faecal contamination may become established as environmental contaminants in waters from which prawns are harvested and have the potential to contaminate free-living prawns prior to catch. Noroviruses and hepatitis A may also be present. Prawns inhabiting estuarine environments may be exposed to a greater number of potential sources of microbial or chemical contamination, due to their proximity to shore, land animals, human dwellings, and the introduction of chemical and faecal pollutants [3]. After harvest, prawns caught on commercial vessels can be processed in a variety of ways. While on board, they may be boxed as green (uncooked) product and chilled or frozen on board. In some operations, catch is cooked on board vessels, and subsequently stored in either brine or ice. Dipping of prawns in metabisulphite to inhibit formation of blackspot can present a risk to asthmatics due to formation of sulphur dioxide. The processing of prawns on board vessels presents considerable potential for further contamination. Raw product may come into contact with chemical or microbial contaminants through contact with water, surfaces or containers. Pathogens of concern include V. cholerae, V. parahaemolyticus, E. coli, Campylobacter, Shigella, Yersinia and Salmonella spp. and L. monocytogenes. Human handling also introduces potential for contamination by enteric pathogens such as Salmonella, S. aureus, hepatitis A virus and noroviruses. Prawns that undergo a cooking step are effectively rendered pathogen free, as any micro-organisms present will be inactivated, assuming that the product is heated at sufficient temperature and time. However, cooking will not remove or inactivate chemical hazards already present in the product, such as arsenic, mercury and other chemical residues. Cross contamination between raw and processed crustaceans during processing, transport and storage, particularly on board vessels, is recognised as an area of particular concern [3,7], potentially reintroducing environmental microbial hazards. Cooling water and brine/ice used for storage of prawns are also recognised as potential sources of recontamination. Cooked crustacea may also be contaminated by food handlers, introducing enteric pathogens. Use of low temperatures during transport and storage (of both raw and cooked product), as well as during processing, will reduce the opportunities for growth of most microbial contaminants if temperatures are rigorously maintained below 5C. However, some pathogens are able to proliferate at temperatures close to this: V. cholerae will grow at 8C, V. parahaemolyticus can grow at 5C [1], and L. monocytogenes is able to grow at temperatures as low as –0.4C [19,20,21]. Once frozen, no further microbial growth can occur, and many pathogens will decline in number with prolonged frozen storage [3]. However, survival rates in frozen crustacea are variable. Time/temperature abuse of thawed product can provide opportunity for growth of any bacterial pathogens that have survived freezing. In some situations, periods of several days may elapse between cooking of prawns and consumption. This time delay provides potential opportunities for outgrowth and further contamination with microbial pathogens, particularly L. monocytogenes. Frequently, consumption of pre-cooked prawns does not include another cooking step, or only one of insufficient time and/or temperature to inactivate these microbial contaminants. Cooked crustacea such as prawns are frequently added to cold dishes which receive only warming, and which are then potentially subject to time/temperature abuse. This may allow bacterial growth and toxin production by contaminating S. aureus. Toxin production may also be enhanced if the seafood is part of a dish with a starch component [7]. This general pattern of processing and consumption represents an area of primary concern to the health and safety of the prawn-consuming public. Aquaculture: Prawn production through aquaculture has been established for the last fifteen years along the eastern coastline of Australia and in the Northern Territory. Australian prawn farms are restricted to the coastal zone, virtually all drawing their intake water from tidal creeks and estuaries. In addition, much of Australia’s import of prawns is produced in aquaculture ponds. In Australia, prawn aquaculture is carried out in earthen ponds, close to tidal sources of seawater. The pond bottoms have a clay base for retaining seawater. Most farmers harvest, process and ship product direct to markets. Harvesting and post-harvest treatments are species specific. Currently Australia grows two species of prawns: the black tiger prawn (Penaeus monodon) and the Japanese king or kuruma prawn (P. japonicus). The black tiger prawn is mostly sold on local Brisbane, Sydney and Melbourne markets, either fresh, frozen or cooked. Typically, black tiger prawns are harvested en-masse with a drain harvest, and then chilled or cooked on site before being shipped to domestic markets. The kuruma prawn is grown exclusively for the live trade to Japan. Like wild-caught prawns, prawns produced through aquaculture may be exposed to various hazards through their water environment. These potential hazards are largely the same as for wild-caught prawns inhabiting estuarine environments, as described above. In intensive aquaculture systems, Vibrio and Salmonella species are considered to be inherent contaminants of prawns [3,10]. Water retained in earthen ponds may be come into contact with chemical pollutants or residues from the surrounding soil, depending on previous land use in the local environment. Further, chemicals and feed components may also be added to pond water, to modify the prawns’ environment. Typically, these may include antibiotics, to combat any pathogens present, and possibly other chemicals with properties that enhance stock growth and/or health. Residues from these chemicals are likely to remain present in the product at time of harvest. Use of such agricultural chemicals and veterinary medicines in the food supply chain is regulated through an agreement between FSANZ and APVMA. All animals grown intensively, under artificially high densities and in contained waters, are prone to disease. Crustacean aquaculture is no exception, with bacterial, viral and parasitic diseases having the potential to affect all life history stages and production phases from hatchery to grow-out. Most bacterial and parasitic diseases are easily identified and treated with better hygiene and limited use of veterinary drugs. Good husbandry practices, including ensuring high water-quality standards, lower stocking densities and the screening of spawners and post-larvae will minimise the occurrence and spread of any viral diseases. Few of these diseases will be of public health and safety concern, being more relevant to the issue of maximising farm production and outputs. However, the use of chemicals and veterinary drugs to control them may present a potential food safety hazard. Prawns produced by aquaculture are subject to the same potential hazards during processing, transport and storage as described above for wild-caught prawns. LobstersLobster fisheries are found in most Australian states (New South Wales, Western Australia, Victoria, South Australia, Tasmania and Queensland), with fisheries for ornate rock lobsters also found in the Torres Strait. The produce is caught mainly using baited pots, though diving and hand spears are also used in some places. A few types of lobster, including Shovel Nosed and Bay Lobsters, are caught mainly as by-product of other fishing operations, such as demersal trawling or dredge netting. Australian lobsters are both exported and sold on the domestic market. Most of the product is sold or exported live or as raw chilled/frozen tails. Lobsters inhabit similar marine environments to prawns, and are potentially exposed to the same environmental hazards, both chemical and microbial. Raw and frozen product are also subject to similar processing and similar potential hazards. Endogenous bacteria that are human pathogens (for example, Vibrios and A. hydrophila) and environmental contaminants (arsenic and mercury) are potential hazards. Post-harvest handling, processing, transport and storage potentially introduce and allow outgrowth of human enteric pathogens (E. coli, S. aureus, Campylobacter, Shigella, Yersinia and Salmonella spp., and noroviruses and hepatitis A virus) and L. monocytogenes. However, as lobster is generally sold either as live or raw frozen product, and is generally cooked thoroughly just before eating, concerns regarding microbiological contamination of cooked product prior to consumption are less relevant than for cooked prawns. CrabsFisheries for two commercial crab species in Australia (Spanner and Blue Swimmer Crabs) are found in Queensland, New South Wales and Western Australia. These are caught in both estuarine and marine waters, using baited tangle nets, or in traps, hoop nets or drag nets. When moving as large aggregations, Spanner crabs are also occasionally caught as a by-product of dermesal otter trawling operations. Cadmium has been identified as a food safety hazard associated particularly with spanner crabs (Ranina ranina). Blue Swimmer Crabs can also be caught as a by-product of prawn trawling or of the rock lobster and finfish fisheries. Wild-caught crabs are generally sold whole, though some are also sold cooked or as crab meat, on either local, interstate or export markets. In addition to these wild-caught species, production of mud crabs through aquaculture is a developing industry in Australia, as well as south-east Asia. Produce from this new industry is typically snap frozen, though a live crab market is also developing. Product is sold on domestic markets, both locally and interstate, or is exported for sale. Crabs inhabit similar estuarine and marine environments to prawns, and are potentially exposed to the same environmental hazards, both chemical and microbial. Raw and frozen product are also subject to similar processing and similar potential hazards. Endogenous bacteria that are human pathogens (for example, Vibrios and A. hydrophila) and environmental contaminants (arsenic and mercury) are potential hazards. Post-harvest handling, processing, transport and storage potentially introduce and allow outgrowth of human enteric pathogens (E. coli, Campylobacter, Shigella, Yersinia and Salmonella spp., and noroviruses and hepatitis A virus) and L. monocytogenes. However, as crab is generally sold either as live or raw frozen product, and is generally cooked thoroughly just before eating, concerns regarding microbiological contamination of cooked product prior to consumption are less relevant than for cooked prawns. Other crustaceans – redclaw crayfish, marron, yabbie and scampiRedclaw crayfish, marron and yabbie are native species of crustaceans that are produced and consumed in Australia. Redclaw are native inhabitants of the rivers of north-western Queensland and the Northern Territory, marron inhabit the river systems of Western Australia, and yabbie are widely distributed throughout central and southern inland Australia. Commercial ventures for production of these species exist in various states, including New South Wales, Western Australia, Victoria and South Australia for marron and yabbie, and Queensland and the Northern Territory for redclaw. Redclaw and marron are produced solely through aquaculture, where they are typically cultured in earthen based ponds. Yabbies are also grown in purpose built ponds, though the primary method of procuring this species is via trapping what are essentially wild yabbies from farm dams. Feed sources for cultured product typically involve a combination of the natural foods found in ponds, and commercial feeds such as crayfish or marron pellets. The primary food source for yabbies is generally crop plants, such as clover, which are grown in the dams they inhabit, though supplementary feed may also be added, and is considered essential to obtain higher than natural yabbie production. Harvesting of stock may take place using a number of methods. Marron ponds are generally drained to allow collection by hand. Redclaw may be collected from growth ponds in a similar manner, or harvested using bait traps, though the most popular and effective method is thought to be the application of a flow-trap. The primary method of harvesting yabbies from dams involves bait pots or traps, or collection after draining. Drop nets can also be used, however it is generally recognised that harvesting yabbies from dams by seine netting damages the animals and can result in bacterial infection from mud stirred up from the bottom [13]. After collection, the harvested animals undergo cleaning. Harvested stock are gill washed and held in purging tanks for a period between twenty-four and forty-eight hours to prevent mortality due to bacterial infections arising from bottom sediments trapped in the gill chamber, and also to allow purging of the hindgut. Produce are then held in a cool, moist atmosphere, and prior to transport are packed between layers of packaging, generally consisting of foam rubber, or wood shavings, in polystyrene boxes with cool packs or ice bottles. Stock can live for many days out of water, and can be shipped alive if transported in a cool, moist atmosphere. Redclaw, marron and yabbie are sold primarily as live export product. Some product is retained for domestic consumption; however, there is little retail sale of the raw product. There are typically three steps in the domestic marketing chain: producer, wholesaler and restaurateur. Only a small portion of product undergoes processing, though some cooking and freezing does take place. The hazards potentially encountered during aquaculture production of redclaw, marron and yabbie are the same as those described for farmed prawns. These include the various chemicals and microbes that may be present in, or added into, the contained water environment. As these three species are predominantly sold live, either on export markets or for domestic consumption through restaurants, minimal processing of the product takes place. Exposure to processing hazards is therefore minimal. However, appropriate conditions (a cool, moist atmosphere) must be maintained during transport and storage of live product to avoid mortality of stock. Dead stock may easily fall prey to contaminating microbes, and cross contamination to live stock packed in close proximity would then be possible. Scampi are commercially fished in north-western waters of Australia, with some species spreading along the northern coast of Western Australia. They are a demersal species, generally inhabiting burrows, and are caught in demersal trawlers similar to those used for prawns. Scampi are graded, packed and frozen whole on board trawling vessels. They are sold on both the domestic and export markets. Volume of catch has varied in the past two decades between ca. 50–200 tonnes/annum [11,12]. Environmental and on-board processing hazards potentially encountered by scampi are similar to those described for wild-caught prawns from marine environments. Endogenous bacteria that are human pathogens (for example, Vibrios and A. hydrophila) and environmental contaminants (arsenic and mercury) are potential hazards. Post-harvest handling, processing, transport and storage potentially introduce and allow outgrowth of human enteric pathogens (E. coli, S. aureus, Campylobacter, Shigella, Yersinia and Salmonella spp., and noroviruses and hepatitis A virus) and L. monocytogenes. Yüklə 2,7 Mb. Dostları ilə paylaş:
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