Lead and arsenic — neither are things you want associated with your cider. If you have an older orchard, however, they may be present.

That’s not just because small amounts of the two toxic chemicals can occur naturally in soil, but they are also the main ingredients in lead arsenate, an insecticide that growers routinely applied to orchards and other field crops in the first half of the 20th century.

Although the insecticide was phased out in the 1950s and officially banned in 1988, the lead and arsenic from those insecticide applications still linger today.

Fortunately, there’s good news, at least in Michigan. Leslie D. “Les” Bourquin, professor in the Department of Food Science and Nutrition at Michigan State University, reports that a comprehensive survey of apple cider samples taken from nearly three-quarters of Michigan cider mills over the last two years found no dangerous levels of lead or arsenic.

Although there are no set federal limits for lead or arsenic in apple juice or cider, the U.S. Food and Drug Administration in 2013 proposed (although it hasn’t finalized) a maximum of 10 micrograms per kilogram for inorganic arsenic, and some wholesale/retail operations follow the lead limit of 30 micrograms per kilogram set by the Codex Alimentarius (international food standards facilitated by the Food and Agricultural Organization of the United Nations).

None of the cider sampled by Bourquin’s group came in above those levels, and most either showed no contaminant at all or very low concentrations.

In all, Bourquin’s doctoral student Loan Cao collected and tested cider samples from 78 Michigan cider mills in 2015 and 82 in 2016, and she also tested 17 samples of shelf-stable apple juice from retail stores in 2015 and 22 in 2016.

Of the nearly 200 samples of juice and cider Cao gathered over the two-year period, tests showed that all but a single sample — one cider — was well below the 10 microgram per kilogram level. In addition, while the tests could pick up arsenic concentrations as small as 1 part per billion (ppb), only 15 to 16 percent of the cider samples had any detectable arsenic. In contrast, 78 percent of shelf-stable apple juice samples showed detectable arsenic.

“In essence, what we’re comparing here is apple juice concentrate diluted with water, (and) the concentrate and water can be a significant source of arsenic,” Bourquin said. “When you’re making cider, you shouldn’t be adding water, so you shouldn’t have too many opportunities for other sources of metal to come into that product.”

For lead, 42 to 47 percent of both shelf-stable apple juice and apple cider had detectable levels (1 ppb), but only one of the samples had levels approaching the Codex limit of 30 micrograms per kilogram.

Overall, the concentrations were all “quite low,” he said. “I would say there’s nothing to be alarmed about.”

Although he gave Michigan cider a clean bill of health, Bourquin said his research group now plans to investigate the relationship between the historical usage of lead arsenate at orchard sites, persisting lead and arsenic concentrations in the soil, and the amount of the two elements in plant tissues, fruit and juice.

The data could have implications in other crops, he said.

“If you’re ripping out old orchards, which happens, knowing prior use before you go in and grow something like carrots or other root crops is going to be really important, because those crops do accumulate much more metal than apples do.” He hopes to have preliminary results from this study by the end of the year.

Bourquin said that while lead and arsenic data from specific cider samples will remain confidential and any reports will only include aggregate data, he invited Michigan orchardists to contact him to receive their individual results. He also invited orchards to participate in the historical-use study.

For information on either, orchard owners should contact Bourquin via email at bourqui1@msu.edu or by phone at 507-353-3329. •

– by Leslie Mertz