In New Jersey, where I live, this time of year is peak harvest season. The farmers markets are full of beautiful, vibrant produce as farmers seek to make the most of the end of their growing season. While there’s nothing as satisfying as a fridge full of fruits and vegetables, the end of the harvest season can also bring some anxiety.
Local fruits and vegetables are wonderful, but in much of the country they are only available for part of the year. During the rest of the year, options seem limited to what we can find on grocery store shelves.
However, it doesn’t have to be that way. Food preservation methods allow anyone to cook with local fruits and vegetables all year round. Whether you’re looking to increase your options for home cooking or guarantee that your business uses local produce year round, food preservation is an excellent tool, especially when done safely and correctly.
General Food Safety Concerns in Food Preservation
The goal of food preservation is to prevent or slow down food spoilage so that we can safely store the food for a long period. With produce, this means extending the time between harvest and consumption.
Food safety is part of preservation and you must preserve the food so that harmful bacteria, molds, and other pathogens don’t cause a foodborne illness.
Every food is different and each method of food preservation has its own potential hazards, but on the whole, food preservation requires a close eye on the raw ingredients, the processing methods, and the storage of the final product in order to ensure safe food to enjoy all year.
Three Food Preservation Methods to Enjoy Local Produce Year-Round
Canning is an excellent way to preserve fruits and vegetables for storage at room temperature. The process is successful when it removes oxygen from the environment of the produce and prevents the growth of bacteria and molds. Canning involves heating the produce and sealing it in an airtight, sterile container. Heating can occur in the container or prior to it being added to the jar or can.
As long as canned food is properly preserved, it will remain safe for years.
The following are the main food safety concerns related to canning:
1. Appropriate Procedures – Canning procedures vary depending on the acidity of the item being canned. Low-acid foods (those with a pH greater than 4.6) need to be pressure canned, while we can seal high-acid foods in a hot water bath. Low-acid foods can also be acidified with the addition of sufficient vinegar or lemon juice or through fermentation, such as with sauerkraut.
Make sure to only use trusted and tested recipes to preserve fresh fruits and vegetables. Give yourself more time than expected to complete the canning, so that you don’t have to rush.
If you are planning to sell canned items commercially, you must have a processing authority approve your scheduled process to ensure that food safety procedures are being followed.
2. Clostridium botulinum – Clostridium botulinum spores may cause botulism, a potentially fatal disease. The spores are found on most fresh food surfaces where they are harmless because they grow only in anaerobic environments (where there is no oxygen).
However, in an oxygen-less, sealed can or jar with low-acidity, there is a risk of C. botulinum spores multiplying and producing a toxin. Botulism is a nasty illness because the toxin is a neurotoxin and blocks our nerves from functioning.
Because of the risk of botulism, when canning any foods with a pH greater than 4.6, you need to seal the jars in a pressure canner and hold the internal temperature of the jars at 240 F for a specific amount of time.
3. Air in the Sealed Jar or Can – Canning is a successful method of food preservation because it prevents exposure to oxygen. If air gets in because of a poor or broken seal, yeasts and molds may grow, spoiling the food.
In order to prevent pathogens from growing, ensure that you have sealed all containers properly before storing. If a can or jar has a swollen lid, air bubbles, a strong odor, or visible mold, dispose of it and do not consume the contents.
Drying is a useful tool to decrease the weight and size of local produce before storing it at room temperature. Using heat to dry causes changes in flavor or texture of the produce, so it may not be appropriate for every fruit or vegetable. Furthermore, drying does not work for some fruits because their sugar content may prevent the removal of all the moisture and the sugars may caramelize causing off flavors.
Drying removes all moisture from the produce. Without water, bacteria, yeasts, and molds cannot grow; thus keeping the food safe.
In order to dry safely, you need an environment that has low humidity, a low heat source, and good air circulation. There are dehydrators that produce this environment but they are not necessary for drying food. You can dry food in your oven as long as it can be held at a low temperature of around 150 F (often the keep warm setting). Leave the door of the oven open and blow a fan to increase air circulation and reduce humidity.
If stored properly, dried food is safe for several months to up to a year.
Food safety concerns with drying include:
1. Drying at too high of a temperature – If the temperature of the oven or dehydrator is too high, the outside of the food can cook before it is dry on the inside. The food items will appear dry on the outside, but still contain moisture on the inside which can lead to mold later on. Don’t dry food at temperatures above 150F.
2. Storing dried food incorrectly – If dried foods are stored incorrectly, moisture will get into the foods and they will spoil. Store dried foods in tightly closed glass jars or heavy duty plastic bags to keep moisture out. Store the jars or bags in a cool, dark place to prolong their shelf life.
Freezing is one of the best ways to preserve produce. Frozen vegetables and fruits have a high nutritional quality, second only to fresh. The freezing process preserves nutrient density, flavor, and, when done correctly, texture. Freezing keeps food safe by holding it at a cold temperature that prevents the growth of pathogens.
When freezing produce, start by freezing individual pieces on sheet trays and transfer the frozen fruits and vegetables to a bag or other container. This prevents the pieces from sticking together. For items that cannot be frozen individually, freeze in small bags then place those bags into a larger bag for storage.
Frozen food will remain safe indefinitely, however quality may decline after a few months.
Food safety concerns with freezing include:
1. Viruses on frozen fruit – Freezing prevents the growth of pathogens while the food is in the freezer, however it does not kill them. Therefore, items that are frozen without having been heat-treated, such as fresh fruit, risk carrying viruses like Hepatitis A. When using frozen fruit, make sure it is virus free or cook it before serving.
2. Freezer burn – Freezer burn is not technically a safety hazard. That said, it can cause a decrease in the quality of the frozen produce. To prevent freezer burn, blanch the vegetables like green beans that are most likely to suffer from freezer burn. You blanch by boiling the prepared vegetables for a minute and immediately cooling in iced water.
3. Incorrect thawing practices – Thawing frozen produce at room temperature can lead to the growth of pathogens. Either cook the product directly from frozen or thaw it in the fridge, under running water, or in a microwave.
Canning, drying, and freezing are all excellent methods of food preservation that extend the shelf-life of local produce, prevent waste from a bumper crop of fruits or vegetables, or help lower ingredient costs.
Each of the methods can occur at home or in a commercial kitchen. In each case, paying attention to food safety is critical to successful preservation and preventing future food-borne illness.
If you’re thinking about how to incorporate food preservation in your commercial production process, but don’t know how to ensure food safety, schedule a free consultation. I would love to help!