Pathogen Reduction in Apple Cider Production

PROJECT BACKGROUND
We operate a 115 acres farm that grows apples, cherries and pumpkins. We also have a seasonal farm market that has an annual attendance rate of over 300,000. We have been producing cider and selling at the retail level for over thirty years. We produce many “value added” products from the things we grow. Items include: cider, caramel apples, pies and other baked goods that use fruit. We have considered these to be sustainable practices.

PROJECT DESCRIPTION AND RESULTS
SARE grant funds were used to determine if Ultrasonic i.e. Ultrasound could achieve an acceptable level of microbial control in apple cider. The Process involved in conducting his research was using a custom built Ultrasound device that was used specifically for apple cider. Approximately one half of the samples were tested for sensory parameters and the other half for microbial parameters. The theory with ultrasonic is to create a cavitation. A cavitation is a violent process that requires a great deal of power to generate. The main goal of the project was to determine if a violent process could be harmful to bacteria and not be detrimental to apple cider quality.

The SARE grant was to lone producer mentioned above. However, other people were relied on extensively to carry out project goals. These included people from the Michigan Department of Agriculture, Michigan State University Extension, and Michigan State University Department of Food Science. From MDA: Jerry Wojtolla and John Tilden, from MSU: Bob Tritten and Dr. Jerry Cash (Extension), Dr. Elliot Ryser, Stephanie Rogers and Pascal Pierre.

Because this was more of a scientific research project the results and discussion are reported more thoroughly in the following report titled Pathogen Reduction in Cider Production. The format it was written in is familiar with the scientific community. To understand this report you have to understand the nomenclature. To measure our success we described steps as Log reductions. For example: a 1 log reduction would be a 90% reduction in bacteria, 2 log reduction is 99% reduction, 3 log would be a 99.9% reduction, 4 log would be 99.99% reduction and so on.

I was hoping that Ultrasound would prove to be better at Log Reduction. The Federal Standard for apple cider producers is a 5 log reduction. I do not think under the best circumstances Ultrasound could achieve a ½ log reduction. I do not think it is possible to create a violent enough cavitation. If I were to try this experiment again I would combine it with another technology to achieve desired microbial results. However, in many sensory evaluations ultrasound treated cider was scored more favorably than untreated. I am excited about the things I learned from this grant. If the technology would have worked it would have been very adaptable for other juice (all types) producers. However, this technology combined with other technologies (i.e. ozone or UV) might be advantageous. I would tell other producers to take a wait and see approach for microbial control in apple cider. Currently there is only two options for cider markers: pasteurization and UV treatments.

Project Impacts:
If this project had been successful the economic impact would only be moderate. A sonication unit would cost between $10,000 and $15,000 depending on size for a single producer.

OUTREACH
I have presented my findings to numerous producers in my field as a part of the outreach of this project. I have shared my findings to producers at the Michigan Horticultural Society Annual meetings, more specifically during the cider session in Grand Rapids, MI. also at the North American Farm Direct Marketing Association National Conference in Mesa, AZ during their cider session. Plus, I shared this information with the members of the Michigan Cider Makers Guild. The guild is a non-profit Co-op with 35 members. Furthermore, this information was shared at Michigan State University Extension, Cider School. This annual school attracts cider makers from across the nation. Plus, this information has been shared with the Michigan Department of Agriculture and Michigan State University department of Food Science. This information will also be given to the Food and Drug Association during their next apple cider comment period.