Although the claim that listening to Wolfgang Amadeus Mozart’s complicated scores can boost your IQ has been debunked, its effect on bananas has yet to be disputed. So in July, the Hyogo Prefecture-based fruit company Toyoka Chuo Seika shipped out its first batch of “Mozart Bananas” to supermarkets in the area.

Arriving as ordinary unripe bananas from the Philippines, “Mozart Bananas” meet an odd fate. “String Quartet 17” and “Piano Concerto 5 in D major,” among other works, play continuously for one week in their ripening chamber, which has speakers installed specifically for this purpose.

Strange as this process may sound, these aren’t the first bananas in Japan to take in the strains of the great 18th- century Austrian composer. A fruit wholesaler in Miyazaki Prefecture started doing it three years ago. In fact, over the past few decades, a wide variety of foods and beverages have been exposed to classical vibrations — soy sauce in Kyoto, udon noodles in Tokyo, miso in Yamagata Prefecture, maitake mushrooms in Ishikawa Prefecture and “Beethoven Bread” in Nagoya, Aichi Prefecture, to name a few.

It’s enough to make the skeptic wonder: Are such producers really serious about the benefits of classical music?

A representative from the Hyogo fruit company, Isamu Okuda, said that it’s no joke, and they believe it makes the bananas sweeter.

“We thought it would be a good investment,” Okuda said, “which would set us apart from the pack.”

The bananas are sold locally in Toyoka for ¥300 a bunch, and compared to last year’s pre-Mozart record, sales are up. The plan is to branch out to big supermarket chains in the future.

Another company that uses this form of enhancement is the Ohara Shuzo, a sake brewery in Fukushima Prefecture. The senior managing director, Fumiko Ohara, said that they started over 20 years ago when the president, Kosuke Ohara, came across a book about brewing with music. They experimented with jazz, Mozart, Bach, and Beethoven, among others.

“We found Mozart works best for sake,” said Ohara, “and that’s why we use only his music.”

For 24 to 30 days, during the third step of the brewing process, Mozart is played for one hour in the morning and one in the afternoon as the sake ferments in enamel-coated stainless-steel tanks. “Symphony 41” and “Piano Concerto 20” do the trick, she explained, but some of his other pieces can work just as well.

“It makes the sake have a richer fragrance and a milder taste,” she said.

Bottles range in price from about ¥1,000 to ¥5,000, and since the 1989 debut of the “classic series,” they have sold steadily, both locally and through mail order.

Although there is no research data to back up the claim that Mozart’s music has any effect on food and beverages, one explanation for its popularity attributes it to theories behind “1/f noise,” or “pink noise,” which is a high frequency sound said to have relaxing and rejuvenating effects on humans. The music of Mozart happens to be rich in such frequencies — those above 8,000 Hz — which is why sound and music therapy both tend to use it. But can what has not been scientifically proven to enhance human performance be beneficial to food, beverages and plants?

This was partially answered by the amateur botanist, Dorothy Retallack, in her 1973 book, “The Sound of Music and Plants.” After playing various kinds of music to plants for three hours daily, she found they “preferred” soothing classical, which made them flourish. Rock and country, on the other hand, had either a debilitating effect or none at all.

A number of food scientists declined to be interviewed for this story because there is not enough research to confidently weigh in on the practice. But that hasn’t fazed Hiroko Harada, the manager of Harada Tomato, based in Tokushima Prefecture. Her shiny Mozart-infused tomatoes, called Star Drops, provide all the proof she needs.

Harada first thought of the idea 15 years ago, after she heard about cows whose milk production went up after listening to Mozart. (A farmer in Spain claims his Mozart-listening bovines produce 1 to 6 liters more milk per day than other cows, and a farm in Aichi called Dairy Paradise uses the same method to boost production.)

At the Harada farm, speakers placed throughout the nine greenhouses quietly stream Mozart for about 10 hours a day, from October through May.

“The most important thing,” said Harada, “is that the music creates a relaxed and comfortable environment for us to work in, and that rubs off on the tomatoes.”

She explained that Star Drops are tastier and sweeter, and according to the Tokushima Kogyou Shikenjyo, a public research institute, they have three times more iron and vitamin C than regular tomatoes. Whether this results from the music or skilled organic farming is hard to say, but Harada feels Mozart plays a role.

In addition to Star Drops, which cost about ¥750 for a 350 gram bag, the company also launched a salad dressing and a tomato puree, all of which sell well, locally and on the Internet.

While the Japanese public seems to have no problem buying the idea that Mozart can enhance food and beverages, the related issue of Mozart’s impact on humans, known as the “Mozart Effect,” has been in the public eye in the West ever since a 1993 study at the University of California, Irvine concluded that Mozart could improve spatial reasoning on the Stanford-Binet IQ test. An avalanche of studies, news reports and products for babies followed, with the discussion always dominated by the IQ question.

According to Don Campbell, the author of numerous books on the subject, including the 1997 “Mozart Effect: Tapping the Power of Music to Heal the Body, Strengthen the Mind, and Unlock the Creative Spirit,” this narrow focus misses out on all that Mozart’s music has to offer.

“Whether or not Mozart raises IQ is not the right question anymore,” Campbell said in a recent telephone interview. “There are better questions to look into that give greater insight into the Mozart Effect. I’m still very pro-Mozart.”

Until a study investigates Mozart’s effect on food and beverages, we’ll just have to take it with a grain of Mozart-infused salt.

If you are interested in checking out the Mozart products yourself, visit: Toyoka Chuo Seika at www.toyookaseika.co.jp, Ohara Shuzo at www.oharashuzo.co.jp, Harada Tomato at www4.ocn.ne.jp/~ha-ra-da. (All sites are in Japanese only.)