Laboratory Testing

Laboratory testing of cider samples will not guarantee a safe product. Cider makers who follow Good Management Practices and apply HACCP principles in their operations (see next section) will have the best chance of producing a safe product. However, if you are going to test for microbes before making and marketing fresh, unpasteurized cider, Escherichia coli bacteria is a good indicator for the presence of pathogens. Take two or more of the worst samples from each orchard supplying freshly harvested apples. The samples must include individual apples normally discarded or trimmed free of disease or damage lesions. If these apples harbor E. coli, they probably have contaminated some sound apples that they may have touched after harvest. Whether you market unpasteurized or pasteurized cider, additional E. coli tests should be made to ensure that operators use hygienic practices and that the operational controls and daily cleanup practices maintain product safety.

Other microbial testing can be used to monitor populations of aerobic acidic bacteria, yeasts, and molds in the facility's environment (air, equipment, surfaces, etc.) and in the cider. Test results should first be used to develop proper operational and cleanup practices and later to confirm that the cider being made is safe and will have a good shelf life.

To develop proper operational practices, samples to be tested should be taken at startup, right after pressing the juice, just after cooling but before bottling, at two or more intervals of time from a single lot of cider stored at your site, and whenever uncertainty exists. Normal aerobic populations in freshly pressed, unpasteurized cider may have from 10,000 to 100,000 bacterial colonies per gram of cider. Normal yeast and mold populations range from 1,000 to 10,000 per gram. Potato dextrose agar acidified to a pH of 3.5 should be used in testing for aerobic populations of aciduric bacteria. Recently, test kits have become available to test E. coli in finished cider. For information, contact your county Penn State Cooperative Extension office.

A list of commercial laboratories in Pennsylvania that provide microbiological services is provided at the end of this chapter.