Corrosion in Tinplate Cans Used for Food Storage, Part 2: Characterization and Corrosion Phenomena in BPA-NI Coated Cans

Abstract

Corrosion phenomena associated with tinplate cans were investigated with aqueous solutions of different compounds commonly found in canned tomato products. After only a few weeks of storage at 49 °C, cans lined with a coating free of bisphenol A (BPA) displayed degradation of the coating. Storage of solutions containing chloride, nitrate, and thiosulfate ions in the BPA-NI coated cans resulted in extensive formation of blisters, which are attributed to cathodic delamination. Additionally, headspace blackening, which is sometimes found in packaged protein-containing foods, was also observed. Volatile sulfur-containing compounds produced during the sterilization process might be the origin of headspace blackening. In this study, the corrosion of tinplate cans exposed to different solutions at 49 °C for varying storage times was studied via optical microscopy, optical profilometry, X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. The results showed a strong correlation between the presence of cysteine, an amino acid, and/or nitrate, and the degradation of the coating. Furthermore, cysteine was found to be a source of headspace blackening.

Criteria and methodologies for determining the causes of swelling of canned tomatoes in tinplate containers

“…The treatment selects the microbial flora from a small group of indicator bacteria (Casolari, 1991; Chapin et al., 2014; Martin et al., 2016; Vicini, 1984) such as lactic and enterobacteria, Bacillus coagulans , butyric clostridia, and thermophilic clostridia, as well as yeasts and molds (Daryaei et al., 2013; Previdi & Previdi, 1991; Riccardi, 2001; Vicini & Zimmermann et al., 2013). This in turn influences the choice and type of container since all acidic or acidified food preserves, such as those based on tomatoes, have the property of corroding the container (Barbieri et al1971; Chang, 2021; Chang et al., 2022; Dhuey, 2019; Montanari, 2015; Palmieri et al., 2002; 2004).…”

“…Similar considerations apply to tomato preserves packaged in coated tinplate cans. For these containers, the interaction between traditional tinplate and canned foods can be minimized by resorting to the use of coated tinplate cans, thus expanding the different classes of acidic and saline food products (Chang, 2021; Lestido‐Cardama et al., 2022; Simal‐Gándara, 1999). From a phenomenological point of view, the internal corrosion of a coated can follows the same scheme as that described above for the uncoated cans.…”