Asst. Prof. Selen Akbulut, Head of Üsküdar University Food Technology Program, evaluated the errors threatening food safety in homemade tomato preserves and sauces, the points to consider in jar and lid selection, and the risk of botulism.
Spoiled and moldy tomatoes should not be mixed with sound ones
Stating that the first step in preparing safe preserves is appropriate raw material selection, Asst. Prof. Selen Akbulut said that the tomatoes used should be of good quality, well-cleaned, and sorted.
Emphasizing that spoiled, moldy, or damaged tomatoes should not be mixed with sound ones, Akbulut said, “The use of spoiled or low-quality material in canning is the most critical point that endangers food health safety and increases the risk of poisoning.”
Akbulut stated that dust, soil, and other contaminants on tomatoes should be removed by effective washing, and noted that the cleanliness of kitchen tools and equipment used during preparation should not be neglected.
Especially the part of the jar that joins with the lid should be checked
Stating that glass jars are a suitable option in preserve production, Dr. Akbulut drew attention to the wear and tear that may occur in the parts of long-used jars that join with the lid.
Dr. Akbulut stated, “In jars that have been used many times, wear and tear occur, especially in the lid crimping areas, due to prolonged use, which poses a risk for spoilage reactions that may occur in preserves.”
Emphasizing that the condition of the lid is as important as the jar, Akbulut recommended using new lids for every preserve preparation. Dr. Akbulut, stating that newly purchased lids should also be checked, said, “Even when new lids are bought, sometimes deformations can occur in the crimping areas. Even if new, checking each lid individually is important here.”
Cleaned material can be re-contaminated with microbes
Dr. Akbulut, stating that cross-contamination is one of the points to be careful about in preserve preparation, explained that cleaned jars and processed foods can be re-contaminated in subsequent stages.
Dr. Akbulut, stating that hands touching raw food or unclean kitchen utensils touching cooked products pose a risk, made the following assessment:
“Touching a heat-treated product in a home environment with a raw food item, contact with an unclean kitchen utensil, touching cooked food after touching raw food will re-contaminate the clean food or packaging, thus compromising the quality of the heat treatment performed beforehand.”
Formation of vacuum does not mean the danger is eliminated
Dr. Akbulut, stating that one of the most serious dangers in homemade preserves is the toxin produced by Clostridium botulinum bacteria, pointed out that the bacteria can grow in an oxygen-free environment. Therefore, she emphasized that the formation of a vacuum in the jar alone does not indicate that the product is safe.
Dr. Akbulut, stating that the bacteria's spores are heat-resistant, said, “The spore structure of the bacteria is resistant to heat treatment. This process, carried out under controlled conditions in factory environments, may not be sufficiently safe in a home environment.”
Akbulut, stating that safety cannot be attributed solely to boiling or the lid's seal, said, “What is important here is the application of a heat treatment process that is suitable for the product's characteristics and has been validated for safety.”
Boiling water treatment also does not provide sufficient safety…
Dr. Akbulut, stating that the acidity of the product is decisive in preserve safety, said, “The pH 4.6 limit is considered a critical limit for Clostridium botulinum. Therefore, pH control of tomato products is particularly important.”
Dr. Selen Akbulut pointed out that processing low-acid vegetable preserves only with boiling water may not provide sufficient safety, and stated, “In such products, a properly defined and validated pressure heat treatment/sterilization process is required.”
If there is swelling, foaming, and leakage, it should not be tasted
Akbulut, stating that lid swelling, leakage, foaming, overflow, bad odor, or noticeable color change are warning signs in preserves, said, “If there is bulging or swelling in the lids of the preserves, if foaming or overflow is observed when the jar is opened, if there is leakage, bad odor, or a noticeable color change, it must definitely be disposed of without tasting.”
Emphasizing that the absence of spoilage symptoms does not guarantee safety, Dr. Akbulut reiterated her warning: “Since Clostridium botulinum toxin may not always produce a distinct odor, taste, or visible spoilage, a normal appearance of the preserve does not mean it is safe. Therefore, suspicious preserves should not be tasted. Even very small amounts of botulinum toxin can lead to severe poisoning.”
Akbulut, stating that small jars can be preferred to facilitate the consumption of opened preserves, concluded by saying, “Therefore, single-serving jars can be preferred instead of large ones.”
