Minnesota Farmers' Market Association

Minnesota Farmers' Market Association

Food Science Library

Whether selling food at a farmers' market or direct from your farm or home, food safety is paramount. Below you'll find links to various science-based articles on food safety. Questions? Email kzeman@mfma.org.

Caution: Canning With Fats & Oils	The exception to using oils in canning is when the recipe has been scientifically tested—of which there are three. The USDA Complete Guide to Home Canning includes tested recipes for marinated whole mushrooms, marinated peppers, and pickled three-bean salad. Each of these recipes includes added acid ingredients (lemon juice, vinegar) as well as preparation steps to ensure adequate acidity of the vegetable. The amount of oil is small, and the acidity is adequate to control the pH. Follow the recipes exactly.
Freeze-dried foods	Any bacteria that were present on the raw food product prior to freeze-drying may become active again. The process of freeze-drying does not kill bacteria but rather slows bacterial growth by reducing its ability to access water.
Fresh, cut fruits in cottage foods	Fresh or raw, cut fruit is a potentially hazardous food because it requires refrigeration to prevent the growth of bacteria that may cause illness when eaten.
Listeria & candied and caramel-coated apples	Based on research following a multistate foodborne illness outbreaks related to caramel apples, caramel apples with inserted sticks are now deemed a potentially hazardous food.
Safe Changes & Substitutions to Tested Canning Recipes
Water activity "Of Frostings and Fillings" from KSU	This project from 2020 was conducted to determine recipes that can be displayed safely at room temperature and those requiring refrigeration. Recipes were submitted by K-State Research and Extension district/county agents and specialists. A total of 49 recipes, some with variations, were submitted and tested in duplicate. Recipes were made in a home kitchen and brought to the Kansas Value Added Foods Lab for analysis. All recipes were tested for acidity (pH), water activity (Aw), and percent soluble solids (% Brix). These factors are crucial to determine the overall safety in the storage environment.
Frosting and Fillings Tested Recipes from KSU	Tested recipes from Kansas State University. Only the recipes that meet pH of 4.6 or below or water activity of 0.85 Aw or below are legal in Minnesota.
Water activity values of a list of select foods	Source: OnlineLibrary.wiley.com (2007)

The Minnesota Farmers’ Market Association (MFMA) provides services, programs, resources, and leadership that strengthen and promote farmers’ markets across Minnesota and Tribal Nations. We envision vibrant, profitable, and professionally managed markets that cultivate thriving local food communities, expand access to fresh and culturally relevant foods, support the success of local food producers, and create opportunities for all people, regardless of ethnicity, age, gender identity, or economic standing.

Contact Us:

Executive Director: Kathy Zeman (She/Hers) | KZeman@mfma.org | (507) 664-9446

Director of Communications and Organizational Development: Pa Thao, MSW (She/Hers/Paj) | Pa@mfma.org | (715) 497-9499

Director of Government Affairs: Friendly Vang-Johnson (She/Hers) | Friendly@mfma.org | (206) 276-2284

Minnesota Farmers' Market Association | 308 East Prince Street | St. Paul MN 55101