Preserves: Essential Guidelines for Safe Preparation

Personal and kitchen hygiene is the first crucial step in preparing preserves. Washing hands with soap and rubbing mechanically is essential to remove microorganisms from the skin. Hands should be washed before starting to handle food and each time you change the type of preparation. Always wash your hands when they appear visibly dirty, after using the bathroom, eating, smoking, coughing, or sneezing, and after touching potential sources of contamination such as raw food, pets, or waste. Dishes should be washed with appropriate detergents and rinsed thoroughly to remove residues. The use of disinfectants like sodium hypochlorite, diluted to 5-7%, is recommended for effective disinfection.

Equipment should be chosen carefully and kept clean. Pots used for water bath heat treatment should be large, with the water level exceeding the jar lid by at least 5 cm. Utensils like wide-necked funnels and plastic spatulas can facilitate filling and removing air from jars. Cooking pots should be stainless steel, while food containers should be glass (noting that clear glass allows light to pass through).

The quality of the ingredients is crucial. Choose seasonal fruits and vegetables, preferably local or organic, to reduce the risk of pesticide residues. Products should be processed within 6-12 hours of harvesting to maintain organoleptic characteristics. Avoid overly ripe or unripe products to ensure the right consistency and flavor in preserves. Vinegar should be wine vinegar, preferably white, with an acetic acid content of no less than 5%. The oil should be of high quality (preferably extra virgin), granulated sugar (or special jam sugar containing pectin), and sea salt.

Wash vegetables thoroughly under running water to remove dirt particles and residues. Soaking in water with baking soda can help reduce surface pesticides. After washing, dry the vegetables, remove damaged parts, and cut according to the preparation needed. Treat products prone to oxidation with lemon juice or by blanching.

Blanching involves heating vegetables in boiling water or steam for a short period. This process stops enzyme action, preserving the color, flavor, and texture of the vegetables. It is important to respect the specific treatment times for each type of vegetable to avoid damage. After blanching, vegetables should be quickly cooled in cold water or ice to stop the heat effect.

Containers must be sanitized thoroughly before use to avoid contamination of the preserved products. This can be done by boiling jars and lids in water for at least 10 minutes or using a high-temperature oven. Sanitization removes any residual microorganisms, preventing the growth of bacteria and molds that could compromise the quality and safety of the preserves. After sanitization, containers should be left to air dry on a clean cloth without touching the inside of the jars or lids to maintain sterility. It should be noted that sanitizing is not sterilizing: the latter is a treatment capable of destroying all microbial forms, including spores, which are very heat-resistant (at a temperature of 100°C the treatment can last several hours).

Filling containers is a delicate operation that requires attention to avoid contamination. Use a clean funnel to pour the contents into the jars, leaving a headspace of about 1-2 cm to allow the product to expand during heat treatment. It is important not to overfill the jars to avoid spills and ensure proper pasteurization. After filling, remove any air bubbles with a plastic spatula, running it along the sides of the jar. Clean the jar rims with a clean, damp cloth to ensure an airtight seal.

Pasteurization is a crucial phase to ensure the safety of preserves. The water bath method is the most common: jars are immersed in boiling water for a time sufficient to destroy pathogenic microorganisms. The duration and temperature of the treatment vary according to the type of product and the size of the jars. For example, fruit preserves generally require a shorter pasteurization time than vegetable preserves. It is essential to follow the specific instructions for each type of preserve to ensure the process's effectiveness.

After pasteurization, jars should be inspected carefully to verify that the lids are properly sealed. A correctly sealed lid should not flex in the center when pressed. If the lid makes a "click" sound in the center, it means it is not properly sealed and the content might be compromised. Store the jars in a cool, dark place, away from direct light and heat sources, to preserve the quality of the preserves. It is advisable to label each jar with the production date and the type of preserve to track their freshness.

After opening, preserves should be stored in the refrigerator and consumed within a varying time depending on the type of product. Acidic or acidified preserves and pickled vegetables can last up to two months, while jams and tomato sauces should be consumed within a week. Sauces, salsas, and fruit juices should be consumed within 4-5 days of opening.