Title: Tampering (crime)
Content:  A famous case involving claims by customers that had tainted the products themselves was a series of claims in 1993 of needles found in Pepsi products. The manufacturer convincingly demonstrated that the contamination could not have taken place at the bottling plant, and several people were proven to have put the needles in themselves.
Title: Tampering (crime)
Content:  Tampering cases often involve foreign objects in food products. These cases often focus on determining whether the contamination occurred during manufacturing, either accidentally or intentionally, or whether the claims made by the complaining customers are real or fraudulent.
Title: Tampering (crime)
Content:  A strawberry tampering crisis where sewing needles were found in a large number of consumer strawberry brands in several Australian states, leading to supermarkets halting strawberry sales for weeks, and forcing farms to dump and burn hundreds of tonnes of produce.
Title: Tampering (crime)
Content:  Tampering can refer to many forms of sabotage but the term is often used to mean intentional modification of products in a way that would make them harmful to the consumer. This threat has prompted manufacturers to make products that are either difficult to modify or at least difficult to modify without warning the consumer that the product has been tampered with. Since the person making the modification is typically long gone by the time the crime is discovered, many of these cases are never solved. The crime is often linked with attempts to extort money from the manufacturer, and in many cases no contamination to a product ever takes place. Fraud is sometimes handled as a matter of civil law, but actual modification of products is almost always a matter of criminal law.
Title: 62 Cases of Jam v. United States
Content:  62 Cases of Jam v. United States, 340 U.S. 593 (1951), was a United States Supreme Court case in which the Court held that "imitation jam," so labeled, was not a "misbranded" product under § 403 of the Federal Food, Drug, and Cosmetic Act of 1938, 21 U.S.C. § 343, even though it did not meet federal regulations for being fruit jam. The form of the styling of this case — the defendant being an object, rather than a legal person — is because this is a jurisdiction in rem (power over objects) case, rather than the more familiar in personam (over persons) case.
Title: Tampering (crime)
Content:  Seven people died in this incident in the United States after taking medication that had been contaminated with cyanide. One man was later convicted of extortion, but no one was convicted of the murders. In 2009, the Federal Bureau of Investigation announced that it was re-examining the case. This event led to new requirements for tamper-evident seals on over-the-counter medications and changes in US tampering laws.
Title: Unilever
Content:  control procedures." An investigation led by Prof. Itamr Grutto and Eli Gordon concluded that the event was caused by negligence. Reportedly the cereals produced between the 18th and 20th at the Arad plant had traces of salmonella. Two class actions were filed in Israel, one for a sum of 1.2 million NIS (~$329K USD) against Unilever for hiding the contamination and misleading the public, and another for a sum of 76 million NIS (~$23m USD) against Unilever after a 15-year-old teen had been hospitalised for Salmonellosis after allegedly contracting it from Unilever products. On 31 August 2016, Unilever stated that the Tehina products produced by RJM had been contaminated by salmonella.
Title: Tamper-evident technology
Content:   Tamper-evident design is perhaps most visible in the process of product packaging and labeling, where it can be vital to know that the product has not been altered since it left the manufacturer. Cans of baby food were among the first high-profile cases, where manufacturers were extorted by persons claiming to have added various poisons to baby food and replaced them on supermarket shelves. The amount of stock which needed to be destroyed (because it was impossible to tell if a given item had been tampered with), and the threat of public fear, meant that tamper-evident design principles had the potential to save a lot 
Title: 62 Cases of Jam v. United States
Content:  The case arose on a libel, that is, an in rem condemnation action filed by the government to seize the jam for being in violation of federal law. The jam, a product called "Delicious Brand Imitation Jam," had been manufactured in Colorado and shipped to New Mexico, where the government libeled it. The jars were assorted flavors of grape, strawberry, apricot, plum, peach and blackberry, and "contained 55% sugar, 25% fruit and 20% of a water solution of pectin." Federal jam regulations, however, as promulgated by the Federal Security Administrator, required that fruit jams contain a higher proportion of fruit to sugars. And although the jars themselves were labeled "Imitation [name 
Title: Chicago Tylenol murders
Content:  The 1982 incident inspired the pharmaceutical, food, and consumer product industries to develop tamper-resistant packaging, such as induction seals and improved quality control methods. Moreover, product tampering was made a federal crime. The new laws resulted in Stella Nickell's conviction in the Excedrin tampering case, for which she was sentenced to 90 years in prison. Additionally, the incident prompted the pharmaceutical industry to move away from capsules, which were easy to contaminate as a foreign substance could be placed inside without obvious signs of tampering. Within the year, the FDA introduced more stringent regulations to avoid product tampering. This led to the eventual replacement of the capsule with the solid "caplet", a tablet made in the shape of a capsule, as a drug delivery form and with the addition of tamper-evident safety-seals to bottles of many sorts.

Question: where did this case of product tampering occur?
Answer: the Chicago metropolitan area.