Biological contamination-free Thai frozen food.

Abstract

The globalization of Free Trade Agreement (FTA) on food products increases the possibility of more extensive transmission of biological contamination. Hazard Analysis Critical Control Point (HACCP) system was introduced as a tool to prevent protectionistic trade. As a major seafood exporter to various regions of the world, Thailand is considering to include the HACCP system for the frozen food industries. Hazard identification of protozoa was performed in raw materials, food products and water used in the industry in 3 Provinces, namely Samut Sakon, Ranong and Songkla. Raw and treated water samples were collected by large volume technique through a filter with 1 μm nominal porosity. Immunomagnetic separation (IMS) for Giardia and Cryptosporidium was then applied to eluted and concentrated water. Identifications were individually performed by immunofluorescent and PCR techniques. In raw water, Giardia was found in 10, 10 and 60% whilst Cryptosporidium was found in 10, 20 and 35% in Samut Sakon, Ranong and Songkla Provinces, respectively. However, no contamination in treated water samples was found. Coli form bacteria was also determined by culture technique, but was not found in any treated water. Giardia was also identified in raw materials and food products. The viability of recovered protozoa was analyzed by the reverse transcriptase polymerase chain reaction (RT-PCR). The giardin betasubunit mRNA gene was selected as the target. Positive RT-PCR for Giardia recovered from raw materials and food products indicates viability. The effect of ultra violet light with the concentration of 10 mWs/cm(2) for 20-100 seconds inactivated viable recovered protozoa, but the sun light exposure was unable to control those viable biohazards. Information gathering from this study suggested that protozoa are important biological hazard recovered not only from water system, but also from raw materials and final frozen food products. We recommended that the critical control points should be applied in all steps including water system by using ultra violet short exposure time as well as raw material and food product systems by controlling human contamination. Further studies concerning tracing the sources of contamination and an alternative methods, which are more sensitive but simple to carry out on an industrialized scale, are needed.