1989 Chilean grape scare

In March,1989, the discovery of two cyanide-laced grapes from Chile in Philadelphia disrupted food trade and affected Chile. The United States Food and Drug Administration (FDA) launched an investigation and stopped all fruit imports from Chile. Although only two grapes were confirmed to contain small amounts of cyanide, the event led to significant changes to Chile's fruit industry and economy.^[1]

Discovery and Initial Response

On March 2, 1989, the United States embassy in Santiago, Chile received an anonymous phone call claiming that Chilean fruit shipments headed toward the U.S had been poisoned with cyanide. ^[1]The Japanese embassy also received a similar phone call. However the caller did not include information about what fruit had been poisoned or what container it was shipped in. That same day the United States Custom Service ordered that all Chilean fruit was not be sent to the public. Then just a few days later, on March 6, the fruits were able to be sent out as the call was determined not credible by authorities^[2].

On March 7, the FDA began investigating the cyanide threats, and the next day they received yet another threat about the poisoned fruit. In response the FDA started more thorough inspections of all incoming produce. On March 12, inspectors found two grapes that tested positive for cyanide. However the amount was small, specifically described by the GAO as not enough to cause sickness in one small child^[2].

Although the amount of cyanide found was minimal, the FDA started a full investigation. The American Produce Association estimated that two million cases of fruit were pulled from shelves in the United States. The import suspension on fruit lasted a total of five days before the FDA and Chile came to an agreement. This agreement was that all Chilean produce needed to pass an inspection in order to be put onto the shelves^[1].

Shortly after, on March 17, there was a third phone call threat, however there were no more contaminated fruit being found. By the middle of April the inspections of Chilean produce returned back to normal^[1].

Although no further contaminated grapes were ever discovered, the scare continued for more than a month and was reported to have created economic and political problems for Chile.

Investigation and Laboratory Testing

After the discovery of the two grapes, the FDA launched an investigation into the grape contamination. According to the United States Government Accounting Office (GAO), the FDA used two different chemical tests ^[2]. The first was a Cyantesmo screening test and the second was a chloramine-T confirmatory test. Both were used to detect the quantity of cyanide in the grapes.

The chloramine-T test found the grapes to have cyanide, and that amount was about 0.51 parts per million ^[2]. This level was far below the amount needed to cause any illness.

The GAO reviewed the FDA's investigation and testing to address the concerns people had about their accuracy and precision. They examined whether the FDA's methods for testing the cyanide were correct, whether any changes to the standard testing procedures affected results, and wether the samples were handled correctly. Overall, the GAO found that their testing was accurate, the sample handling was not tampered with, and the results were supported^[2]. The GAO's review was conducted in response to questions raised, more specifically by the Chilean government, about the testing legitimacy.

Scientific Context

Toxicology of Cyanide

Cyanide is a fast acting chemical that affects how living cells use oxygen. When it enters our bodies, it binds to enzymes in the mitochondria, which stops cells from converting oxygen into energy. This prevents tissues from accessing usable oxygen even when the oxygen is available ^[3].

In animals, including humans, once cyanide is present, it can interfere with our cellular respiration, which is essentially how the body turns food and oxygen into energy. To protect itself from small amounts of cyanide, the body uses an enzyme called rhodanese to change it into a less harmful compound which can then be removed.^[4]

Challenges in Detecting Cyanide

Testing for cyanide in fruit can be difficult because the compound can break down or react in moist, acidic conditions found in grapes. The natural chemicals that are found in fruits like sugars and organic acids^[5] can also interfere with and alter test reactions, which makes it more difficult to get precise results.

In the FDA's investigation the two chemical tests were the Cyantesmo screening test and a chloramine-T confirmatory test^[2]. The cyantesmo test was used to quickly check for hydrogen cyanide, while the chloramine-T test was used to measure the amount of cyanide in the grapes. As stated earlier, these tests allowed for the FDA to detect 0.51 parts per million of cyanide in the grapes.^[2]

Natural Production of Cyanide in Plants

Plants can produce compounds called cyanogenic glycosides, which are molecules that include a sugar part and another part that can release cyanide under certain conditions.^[6] These compounds are stored in a different location from the enzymes that can break them down, which keeps the cyanide harmless.^[7]

When plant tissue is damaged, which could be caused by being crushed or bruised, the enzymes come into contact with the glycosides and start a reaction that then releases hydrogen cyanide gas.^[7] This process is called cyanogenesis, which happens when plant enzymes break down certain compounds and release cyanide gas, along with some sugar and other molecules.

Economic and Political Impact

The grape scare took place during a challenging period for Chile's economy. At the time, Chile's fruit export industry was an important source of income and employment. The sudden U.S. ban on all fruit imports from Chile disrupted the trade, which caused economic and social losses. Over time, the crisis also caused political tension, and legal issues.

Short Term Effects

In the days after the ban, Chilean fruit exports experienced difficulties. Shipments that were already on their way were delayed, and packing facilities suspended operations while inspections began. The Chilean government agreed to allow all fruit exports to be inspected before being shipped.^[1]

According to the GAO, approximately 47 million crates of fruit had already been exported out of an expected 103 million for the season before suspension took occurred^[2]. The temporary pause in trade caused significant employment and economic challenges. It is estimated that around 20,000 workers in the Chilean fruit sector lost their jobs during this period of time.^[1]

Long Term Effects

Although the ban lasted only a few days, the Chilean fruit industry faced lasting consequences. Chilean workers, both farmers and exporters, filed lawsuits seeking compensation for financial losses which were estimated to be around $200 million. One lawsuit in particular was seeking $330 million in damages. Many of these lawsuits ended up being unsuccessful, however they did show the extent of the consequences. ^[1]

The incident reportedly affected Chiles overall reputation internationally. Some foreign buyers and governments increased their inspection and regulations on Chilean produce following the event. ^[1]