The concentration of potentially toxic elements (PTEs) in the coffee products: a systematic review and meta-analysis

A multi-year heavy metal analysis of 72 dark chocolate and cocoa products in the USA

Introduction

Contamination of cocoa containing products, such as dark chocolate, with heavy metals including lead, cadmium and arsenic has been reported in the US. However, a formal exploration into the significance of this contamination, nor multi-year trends in the degree or scope remain unresolved.

Methods

From 2014 to 2022, 72 consumer cocoa-containing products were purchased and analyzed for heavy metal contamination with lead (Pb), cadmium (Cd), and arsenic (As) in 4 distinct cohorts (2014, 2016, 2019, 2022). The thresholds used to assess heavy metal contamination were set to Prop 65 maximum allowable dose levels (MADLs) of 0.5 mcg/day, 4.1 mcg/day, 10 mcg/day for Pb, Cd, and As, respectively.

Results and discussion

Our analysis reports that 43, 35, and 0% of the products tested exceed Prop 65 MADLs for heavy metal concentrations, respectively, of Pb, Cd, and As, while 97.2% (70 of 72) fall below US FDA IRL limits established for Pb. Median concentrations of each metal tested were lower than even the conservative Prop 65 MADLs, indicating a potentially large effect of product outliers. This indicates that heavy metal contamination-in more than half of products tested-may not pose any appreciable risk for the average person when consumed as a single serving; however, consuming some of the products tested, or more than one serving per day in combination with non-cocoa derived sources heavy metals, may add up to exposure that would exceed the Prop 65 MADLs. Notably, "organic" products were significantly more likely to demonstrate higher levels of both Cd and Pb.

Dietary Intake of Minerals and Potential Human Exposure to Toxic Elements via Coffee Consumption

In this study, we investigated the levels of macro, minor, and trace elements in roasted ground and instant coffees (n = 56). We assessed dietary mineral intake and health risks associated with potentially toxic elements (PTEs) using deterministic and probabilistic approaches. The limits of detection (LOD) ranged from 0.13 µg/kg for Be to 3.7 mg/kg for K, with corresponding limits of quantification (LOQ) at 0.43 µg/kg and 12.2 mg/kg. The recovery values (R%) ranged from 89 to 107%. The most abundant element was K, followed by Mg, Ca, and Na. Other elements followed this order: Fe > Mn > B > Cu > Sr > Zn > Al > Ba > Ni > Cr > Co > Se > Sn > Pb > Li > Ag > V > As > Cd > Hg > Be. Instant coffees generally exhibited higher K, Mg, and Na levels than ground-roasted coffees. Notably, Hg, Li, and Se were not detected in 34, 2, and 1 samples, respectively. Coffee samples were generally a good source of dietary elements such as Cu, Mn, Cr, and Se. The PTEs found in coffee products posed negligible risks to human health. The total target hazard quotient (TTHQ) remained below 1, and the incremental lifetime cancer risk (ILCR) did not exceed the threshold of 1 × 10-6. Nevertheless, coffee consumption contributed to Pb and As levels below 15% of the benchmark dose lower confidence limit (BMDL) values, and Sn, Hg, and Cd levels below 0.90% of the provisional tolerable weekly intake (PTWI).

Preliminary Investigation on Hygienic-Sanitary Quality of Food Vending Machines

The consumption of hot drinks dispensed from vending machines has become a common practice, both in workplaces and during free time. Every day, millions of bulk drinks are sold, but the quality of the products distributed may not always be guaranteed, as it is related to many factors such as the quality of the water, the raw materials used, and the effectiveness of the equipment's cleaning system. The purpose of this study is to evaluate the hygienic-sanitary requirements of hot drinks and vending machine surfaces. The investigation highlighted the microbial contamination of both coffee and vending machine surfaces. Although the "coffee break" is usually considered a moment of pleasure, apparently not subject to specific jurisdiction, the products dispensed can represent a health risk if the hygienic conditions are not fully respected. Therefore, official controls carried out by the Prevention Department represent a suitable way for evaluating and guaranteeing the hygienic-sanitary requirements, providing for corrective actions, when needed, to protect consumers.