Reports

Styrene migration from expanded polystyrene boxes into fresh cod and redfish at chilled and superchilled temperatures

Published:

01/12/2017

Authors:

Erwan Queguiner, Björn Margeirsson, Sigurjón Arason

Supported by:

RPC Tempra

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Styrene migration from expanded polystyrene boxes into fresh cod and redfish at chilled and superchilled temperatures

The aim of the experiment was to investigate the possible flow of styrene from foam plastic boxes to fresh cod and redfish fillets, which are stored at typical temperatures during sea transport of fresh fillets from Iceland to Europe or America. US buyers want fish fillets to be packed in plastic bags before packing in a foam box due to possible styrene contamination from foam to fish. Therefore, in this project, styrene was measured in fish, which had been stored without plastic bags in foam boxes, and the amount of styrene was compared with the standards of the US Food and Drug Administration (FDA). A total of 12 foam boxes containing cod or redfish fillets were stored for 4, 7 or 13 days at either -1 ° C or 2 ° C, which corresponds to the optimal and highest probable temperature in fresh fillet shipping. One 10-50 g sample was taken from the lower part of the bottom fish fillet in each box and had thus been in direct contact with foam plastic and therefore placed in a glass bottle. Subsequently, the 12 samples were sent for analysis to Eurofins, an international laboratory in Germany. The results show that the amount of styrene, as well as other undesirable substances such as benzene and toluene, was below 0.01 mg / kg fish in all twelve fish samples. The FDA guideline (maximum) is 90 mg of styrene per kg of fish per person per day, which is equivalent to The result of this experiment is that a consumer has to consume 9000 kg of fish daily to meet the FDA standard, which is a very unrealistic amount. The main conclusion of this experiment is that it is not necessary to pack fresh fish fillets in plastic bags for packing in foam boxes, which are stored and transported in refrigerated and supercooled conditions.

The aim of the study was to investigate possible styrene migration from expanded polystyrene into fresh cod and redfish, two important export fish species in Iceland, while stored under conditions mimicking transport by ship from Iceland to America and Europe. American buyers wish to have a plastic bag between EPS boxes and fish during transport as a safety measure due to possible styrene migration. Thus, this project was conducted to investigate if adding a plastic bag is necessary with regards to safety limits for styrene migration from packaging to food set by the FDA (US Food and Drug Administration). A total of twelve samples of cod and redfish were stored in EPS boxes manufactured by Tempra ltd. for 4, 7 and 13 days at two temperatures (-1 ° C, 2 ° C) which represent optimal and expected maximum storage temperatures during sea transport of fresh fish. A sample of 10-50 grams of fish, which had been in direct contact with the packaging, was taken from the bottom of each box, as it is considered the most hazardous place regarding styrene migration, and put in a glass bottle before analysis. Finally, the twelve samples of fish were sent to Eurofins, an international laboratory in Germany, for analysis. The results show that styrene content, and other solvent residues like benzene or toluene, were below 0.01 mg / kg in all twelve samples of fish. The FDA's daily intake limit of styrene is 90 mg / kg per person per day, which means that in this study an unrealistic intake of at least 9000 kg of fish would be necessary to exceed this FDA´s limit. The main conclusion from this study is therefore that a plastic bag is not needed to safely pack cod and redfish fillets into EPS boxes to be stored under chilled and superchilled temperatures.

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Reports

Guidelines for precooling of fresh fish during processing and choice of packaging with respect to temperature control in cold chains

Published:

01/12/2010

Authors:

Kristín Líf Valtýsdóttir, Björn Margeirsson, Sigurjón Arason, Hélène L. Lauzon, Emilía Martinsdóttir

Supported by:

AVS Fund of Ministry of Fisheries in Iceland (R-037 08), Technology Development Fund at the Icelandic Center for Research (081304508), University of Iceland Research Fund and EU (contract FP6-016333-2)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Guidelines for precooling of fresh fish during processing and choice of packaging with respect to temperature control in cold chains

The purpose of the guidelines is to assist in the choice between different methods of pre-cooling fresh fish products as well as to assist in the selection of packages with regard to the heat load that the product experiences on its way from producer to buyer. The following pre-cooling methods are discussed: liquid cooling, sludge cooling and skin cooling (CBC, touch and blow cooling). The treatment of products during processing and the effect of different refrigerants on temperature control, quality and shelf life of fillets before packaging the product are also discussed. The guidelines take into account the processing of lean whitefish, such as cod and haddock. The results of research show that a well-designed pre-cooling before packing can result in a shelf life of 3 - 5 days longer due to no pre-cooling before packing. Inadequate fluid exchange during hydraulic cooling with associated cross-contamination can, however, negate the positive effect of pre-cooling. Icelandic fresh fish producers mainly use expanded polystyrene (EPS) and corrugated plastic (CP) boxes for the export of fresh fillets and fillet pieces. Therefore, only the aforementioned packaging types are discussed here. The conclusion is that if the temperature control is inadequate and the temperature fluctuations are high, it is desirable to use foam plastic boxes that provide better thermal insulation than corrugated plastic boxes.

The aim of the guidelines is to provide and assist with choice of different precooling techniques for fresh fish fillets as well as assist with choice of packaging with respect to thermal abuse, which the product experiences during transport and storage from processor to customer. The following precooling techniques are discussed; liquid cooling (LC), slurry ice cooling (SIC) and combined blast and contact cooling (CBCC). In addition, the following is discussed; handling during processing and the effect of applying different cooling media before packaging on temperature control, quality and shelf life of fresh fillets. The guidelines are designed with lean white fish muscle in mind, such as cod and haddock. The results reveal that efficient precooling before packaging can prolong shelf life up to 3 to 5 days compared to no precooling before packaging. If the liquid exchange in the liquid cooler's circulation system is insufficient, cross-contamination can diminish the positive effects of precooling. Icelandic fresh fish processors mainly use expanded polystyrene (EPS) and corrugated plastic (CP) boxes for export of fresh fish fillets. The guidelines are therefore only focused on the above-mentioned packaging types. The conclusion is that if temperature control is unsatisfactory and temperature fluctuations are great, then expanded polystyrene boxes are the preferred alternative because they provide better insulation.

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