Microplastic Contamination of Chicken Meat and Fish through Plastic Cutting Boards

Abstract

Microplastic contamination was found in fish and chicken bought on the market, in food stores and in chain supermarkets in the Middle East with the contamination ranging from 0.03 ± 0.04 to 1.19 ± 0.72 particles per gram of meat in chicken and from 0.014 ± 0.024 to 2.6 ± 2.8 particles per gram in fish. Only one fish was found to be free of microplastic. The source of the microplastic was established to be the polythene-based plastic cutting board the food was cut on. More microplastic contamination was found in food cut from the bone than in cut fillets when the fillets themselves were prepared on surfaces other than plastic. Washing the fish and chicken before food preparation decreased but did not completely remove the microplastic contamination. The fate of the microplastic in grilled fish was studied. The mechanical properties of typical plastic cutting boards commercially used in the markets were investigated in the form of tensile, hardness, and wear tests. Overall, the plastic cutting boards showed similar wear rates.

Keywords: food contamination; food preparation; microplastics; plastic cutting boards; wastewater.

Figure 1

Examples of cutting boards used by markets with corresponding generated microplastic fragments (upper left corner, photos taken with microscope Olympus model BX41TF) and surface texture of the cutting boards (lower right corner, photos taken with stereoscope model SZ2-ILST): (a) CB-1 (white/colorless); CB-2 (red); CB-3 (green); CB-4 (yellow) where are (b–d).

Figure 2

Original photos (a,b) and photos processed with Image J (c,d) of MP obtained through the digestion of (a,c) chicken sample 3 (C3) and (b,d) orange-spotted trevally (F5).

Figure 3

(a) MP stemming from cut raw king mackerel (Scomberomorus cavalla) after digestion with aq. KOH; (b) part of a grilled king mackerel piece with adhering MPs; (c,d) MPs isolated from the grilled king mackerel.

Figure 4

Differential scanning calorimetry (DSC) curves of polythene material from CB-3 (right) and CB-4 (left).

Figure 5

Prepared tensile specimens of CB-3 (a); CB-4 (b); fractured tensile specimens of CB-3 (c); and CB-4 (d).

Figure 6

Stress-strain curves of the plastic cutting boards: (a) green cutting board (CB-3); and (b) yellow cutting board (CB-4). Five tensile specimens were prepared from each cutting board to determine the mean tensile strength of the cutting boards. The different colored lines show the stress-strain curves obtained from tensile tests of the five specimens. It can be observed from the figure that very consistent tensile strength values were obtained for all the five specimens.