The 2014 Basil Pine-Nut Botulism Outbreak
Investigators at the City of Cincinnati Health Department and the Ohio Department of Health quickly confirmed that two women had shared a meal of pasta with chicken and jarred pesto sauce. During a visit to one victim’s apartment, investigators found leftover chicken pasta with pesto in the apartment refrigerator. The leftovers, as well as the remaining unopened jars of pesto, were collected for laboratory testing for the presence of C. botulinum toxin. On July 29, Ohio investigators notified the CDC, FDA, and California Department of Public Health (CDPH) Food and Drug Branch (FDB) that two Ohio residents had been infected with botulism and that the suspected source was VR Green Farms (VRGF) Basil Pine Nut Pesto. CDPH-FDB contacted Dominic Romano, owner of VRGF, and informed him of the infections that had been linked to his pesto product.
Acting quickly, California investigators visited the VRGF Farm Stand on the following day. It was then learned that a variety of canned products were produced seasonally and sold at the stand. Most of the products sold there had been produced on behalf of VRGF and Romano at facilities that were neither registered nor permitted. Mr. Romano was advised that he must immediately cease the unlicensed manufacturing and sale of low acid canned and acidified foods. A Notice of Violations was issued to Mr. Romano for the unlawful production and sale of food. VRGF initiated a recall of all suspect low acid canned and acidified foods. In addition, the CDPH issued an alert, warning consumers to not eat VRGF jarred products because of improper production that had made them susceptible to contamination with Clostridium botulinum.
As the California investigation continued, investigators learned that Rose Schwinn, doing business as Rose’s Artisan Creations, had manufactured the pesto sauce for VRGF and Romano some time in April or May of that year. Ms. Schwinn was a family friend of Dominic Romano. Mr. Romano initially informed investigators that only 10 to 12 jars of pesto sauce had been made as a test product. But this information was soon found to be inaccurate. On July 31, CDPH investigator, Melissa DeHart, contacted Ms. Schwinn to discuss manufacturing processes. Ms. Schwinn reported that she had manufactured the product in her home kitchen and that she had made small batches of various products sold at the Farm Stand “on and off for a few years.” It was also confirmed that Ms. Schwinn had not obtained a CDPH Processed Food Registration or a Cannery License, as was required to manufacture these types of foods for retail sale.
Rose Schwinn described the process used to make the pesto sauce. Raw garlic cloves and salt were ground in a food processor. Fresh basil leaves and olive oil were added and then mixed with pine nuts and Parmesan cheese. Because of the small size of the food processor, ingredients were processed in small batches and the resulting mixture was added to a large pot until she had made the desired amount. The pesto-mixture could sit for up to one hour at room temperature before it was filled into the jars. The mixture was not cooked or otherwise subject to a heat step.
New jars were cleaned by placing them in her household dishwasher on the hot cycle with dish detergent and bleach. The jars were then filled with water and heated in the microwave until the water boiled. After the hot water was poured out, Ms. Schwinn filled the jars with the pesto-mixture. The lids were kept in hot water until needed. Once the lids were on, the jars were placed into a stove-top canning-unit. The water in the canning-unit was brought to a boil and the jars filled with the pesto-mixture were heated to an unknown temperature. A thermometer was not used. The jars were allowed to cool, the seal around the lid checked, and the product was labeled for distribution. The label did not include a complete ingredient statement, lot code, “Best By” date, or a “Perishable Keep Refrigerated” statement. CDPH described the process that Ms. Schwinn used as having been conducted under “insanitary conditions at a home residence.”
The CDPH Food and Drug Laboratory Branch (FDLB) collected an unopened jar of VRGF Basil Pine Nut Pesto from Rose Schwinn. The sample was tested for pH, water activity, and ELISA screening for C. botulinum. Test results showed that, for sample #062080514, the pH was 5.3 and the water activity was 0.965. Non-refrigerated foods that are packed in hermetically sealed jars with a pH above 4.6 and water activity above 0.85 are at risk for supporting C. botulinum toxin formation and must be manufactured in accordance with an approved scheduled process, controls, and pursuant to a Cannery License. Clearly, VRGF Basil Pine Nut Pesto did not meet the minimum requirements for food safety. Investigators determined that VRGF Basil Pine Nut Pesto placed “consumers of the product at risk for C. botulinum toxin illness.”
Coincident with the California investigation, state public health laboratories in Ohio also tested several samples of the pesto. The Ohio Department of Health Bureau of Public Health Laboratories tested two unopened jars collected from private residences, including leftover chicken pasta with pesto. Although no toxins were found in the unopened jar that was tested, the leftover pasta meal tested positive for Clostridium botulinum toxin type B. Of the two jars that the purchaser had dropped off in Colorado, one jar had been consumed with no ill effects. The second jar had a swollen lid and was shipped to Ohio for testing, but no C. botulinum toxins were found in this unopened jar.
CDPH FDLB also tested the unopened jar of pesto that the purchaser still had in his possession. This jar showed low levels of C. botulinum toxin B by Luminex system testing and “borderline” testing results by ELISA, but definitive testing by the mouse bioassay was negative.