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This study deals with nonsterile canning of double concentrate tomatoes (30° Brix) stored for 210 days at three different temperatures (4, 10 and 25C) in 200 kg drums. the evolving analytical composition (soluble solids, total solids, glucose, fructose, pH, total acidity, volatile acidity, citric acid, malic acid, succinic acid, hydroxymethylfurfural (HMF) and color parameters) that the product underwent during storage was dependent both on storage temperature and on different aerobic levels within the drum (top and bottom sections). the microbial profile (yeast, lactic acid bacilli and molds) was correlated with many important metabolites (D‐ and L‐lactic acids, ethanol, acetic acid and diacetyl). the results indicate that the increase of these substances is dependent both on storage temperature as well as the oxygen tension within the drums. Taken all together, the analytical findings offer a great help in evaluating the quality of semifinished tomatoes. We also found that lactic bacteria grow rapidly at 25C and after 15 days their number from both sampling areas in the drums (i.e., 10 cm below the sample surface and 15 cm above the bottom of each drum) is already greater than 105 cfu/ml. At 10C, 30 days were needed to reach such a cell concentration, and after 45 days the level reaches 107‐108 cfu/ml. By contrast, at 4C there were differences between top and bottom sampling areas. In the top area, 105 cfu/ml was reached after 60 days, while for the bottom area this was reached after 120 days. Regarding yeast at 25C.

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This review provides the current laboratory criteria for the detection and evaluation of the possible causes of alteration of non‐concentrated industrial derivatives of tomatoes (peeled tomatoes, pulps, purees, sauces, and fillets), packaged in coated or uncoated tinplate cans. We discuss how the product alterations are typically the consequence of technological errors either in the can production, or in the storage process, or in the product sterilization. The described procedures include the quantitative determination of the distribution of gases (H2, CO2, N2, and O2) present in the headspace of the container. The gas composition and ratios can be used as markers to allow easy diagnosis of the causes of microbiologic and/or physical–chemical alterations of the tomatoes, which are usually made evident by swelling of the containers. These tests should be integrated by microbiological analyses aimed at a restricted group of microorganisms, with the chemical analysis of the container and the chemical analysis of the altered product. By way of example, we report the assessment of the causes of alteration in four different case‐studies.