Assessment of the safety of aquatic animal commodities for international trade: the OIE Aquatic Animal Health code.

Trading of aquatic animals and aquatic animal products has become increasingly globalized during the last couple of decades. This commodity trade has increased the risk for the spread of aquatic animal pathogens. The World Organisation for Animal Health (OIE) is recognized as the international standard-setting organization for measures relating to international trade in animals and animal products. In this role, OIE has developed the Aquatic Animal Health Code, which provides health measures to be used by competent authorities of importing and exporting countries to avoid the transfer of agents pathogenic for animals or humans, whilst avoiding unjustified sanitary barriers. An OIE ad hoc group developed criteria for assessing the safety of aquatic animals or aquatic animal products for any purpose from a country, zone or compartment not declared free from a given disease 'X'. The criteria were based on the absence of the pathogenic agent in the traded commodity or inactivation of the pathogenic agent by the commercial processing used to produce the commodity. The group also developed criteria to assess the safety of aquatic animals or aquatic animal products for retail trade for human consumption from potentially infected areas. Such commodities were assessed considering the form and presentation of the product, the expected volume of waste tissues generated by the consumer and the likely presence of viable pathogenic agent in the waste. The ad hoc group applied the criteria to commodities listed in the individual disease chapters of the Aquatic Animal Health Code (2008 edition). Revised lists of commodities for which no additional measures should be required by the importing countries regardless of the status for disease X of the exporting country were developed and adopted by the OIE World Assembly of Delegates in May 2011. The rationale of the criteria and their application will be explained and demonstrated using examples.

From eco-sustainability to risk assessment of aquaculture products.

The increasing demand for fishery products and the technical and commercial opportunities now available make the development of aquaculture an important subject for the policy of the fishery sector, in particular concerning aspects of its environmental and ecological sustainability. The latest studies show that it is possible to apply an ecological approach to the aquaculture sector and hence increase the interactions between fisheries and other activities such as fish/molluscs, fish/seaweed, rice-growing/fish. In this way we take part in the improvement of the environment thanks to the recycling of organic food, the reduction of pesticide use and the control of environmental euthrophication. In order to support and facilitate trade, but at the same time ensure the safety and quality of products, a harmonization of the policies for food safety protecting the products throughout the whole food chain is required (from the sea to the table). The above mentioned policy, based on scientific knowledge, relies on the analysis of risks from the competent Authorities and on the proper application of HACCP from the industries of the sector.

Potential of Listeria hazard in African fishery products and possible control measures.

Africa contributes 5.54 million MT (4.5%) to the world harvest of aquatic organisms. Fisheries represent a vital sector for many countries in Africa, both for domestic food supply, employment opportunities and foreign exchange earnings. Despite the low level of African fish production and export in comparison with the other continents, fish represent the major protein Source in many countries (36-58% of animal proteins in C te d'Ivoire, Congo, Senegal, Angola) and fishing is a vital activity for Senegal, Mauritania, Morocco, Ghana, Tunisia and other countries. In fact, it is the main sector for foreign exchange earnings in countries such as Senegal and Mauritania (Ababouch, 1998b; 1999). Consequently, expansion of export and development and production of value-added products in Africa for export are strategic keys for future economic development. This will require the implementation of reliable in-plant HACCP-based quality and safety control systems. Unfortunately, very little in known about the prevalence and ecology of Listeria in food, especially as it relates to seafood safety. This paper discusses the potential of Listeria hazard from African fishery products and speculates on some possible control measures.

Thermal inactivation kinetics of Bacillus subtilis spores suspended in buffer and in oils.

The heat resistance of Bacillus subtilis 5230 and A spores freeze dried and suspended in buffer or oils was investigated. As expected, spores were more resistant to heat when suspended in oils than in buffer. This was ascribed to the low aw of oils and to their content of free fatty acids. Linear survivor curves were obtained for spores suspended in buffer at 105 degrees C or above and for B. subtilis A spores suspended in a vegetable oil. However, the survivor curves of the spores suspended in mineral oil (strain 5230) or olive oil (both strains) were concave upward with a characteristic tailing. The tailing could not be ascribed to spore clumping or to a specific heat injury that can be circumvented by Ca-dipicolinate. It is possibly due to another mechanism of injury or to the activation at high temperature of a normally dormant germination system.

Effect of thermal treatments in oils on bacterial spore survival.

The heat resistance of Bacillus cereus F4165/75, Clostridium sporogenes PA 3679 and Cl. botulinum 62A spores suspended in buffer (pH 7.2), olive oil and a commercial oil (a mixture of rapeseed oil and soy oil) was investigated. Linear survivor curves were obtained with B. cereus spores in the three menstrua and with 62A and PA 3679 spores suspended in buffer. However, the inactivation kinetics of the clostridial spores suspended in oils were concave upward with a characteristic tailing-off for 62A spores suspended in olive oil. These deviations from the semi-log model could not be ascribed to a heterogeneity in heat resistance of the spore population or to the variation of aw during heating. Spore resistance to heat increased in the order: buffer much less than commercial oil less than olive oil. The greater heat resistance of oil-suspended spores was ascribed to the low aw (0.479 and 0.492 for commercial oil and olive oil, respectively) and to the composition of the oils. The difference in z values (ca 28 degrees C in oils and 10 degrees-12 degrees C in buffer) suggested that the mechanism of inactivation differs for spores suspended in lipids and in aqueous systems. The thermodynamic data were consistent with this hypothesis.

Tailing of survivor curves of clostridial spores heated in edible oils.

Tailing of survivor curves was observed for Clostridium sporogenes PA 3679 and Cl. botulinum 62A spores heated whilst suspended in edible oils, but not for the same spores suspended in buffer (pH 7.2) or mineral oil or for Bacillus cereus F4165/75 spores suspended in buffer or oils. The tailing cannot be ascribed to a genetic or developmental heterogeneity in the resistance of the spore population or to a heterogeneity of the treatment severity during heating. Heat adaptation due to the release of protective factor(s), to the selection for resistant spores or to the diffusion of oil constituents inside the spore protoplast to protect key molecules from heat denaturation was also ruled out. The tailing can be ascribed to spore clumping during the course of heating or to a heterogeneity in heat resistance of germination system(s) within spores, concurrently with the activation of a dormant germination system. It is probably caused by some oleic acid containing triglycerides.

Histamine Levels in Commercially Processed Fish in Morocco.

Histamine levels were determined in 248 samples of fish commercially processed in Morocco. Concentrations ranging from <0.01 to 694 mg/100 g of fish (mg%) were observed. The mean value was 12.33 mg% (sardines, 9.75; mackerel, 13.74; tuna 9.86) and the standard deviation was 55.28 mg% (sardines, 43.21; mackerel, 71.99; tuna, 25.05). The bulk of the samples (85.5%) had low histamine levels (<10 mg%); 26 samples (10.5%) had levels within the range 10-50 mg% and should be classified as not from fresh fish or of low quality; 10 samples (4%) had toxicologically significant levels, above 50 mg%. Tuna fish was more susceptible to histamine development than were sardines or mackerel; 7% of tuna fish samples contained levels above 50 mg% as compared to 3.7% and 3.2% for sardines and mackerel, respectively. The percentage of samples containing levels above 50 mg% was somewhat higher for fish processed in the central region (7.1%) than the southern (4.3%) or northern (1.3%) regions; however, statistically the regional differences were not significantly different. Histamine development in sardines demonstrated first-order kinetics. Reaction rates ranged from 0.00200 to 0.000421 mn-1. Refrigeration controlled histamine development. Fish held at 8°C showed a shelf life 12 h longer than fish held at 17°C. A combination of salting and refrigeration was more effective. Fish held at 8°C and salted at a level of 5 or 8% showed a shelf life 35 h longer than fish held at 17°C with no salt.