Locally processed milk contained bacteria levels in excess of federal limits five days before the "sell-by" date, according to preliminary findings from a new University of Hawai'i study.

The study, by UH dairy extension specialist Chin Lee, provides the first scientific evidence that in some cases O'ahu milk may be susceptible to souring before its expiration date.

Meadow Gold Dairies, the sole milk processor in Hawai'i, said its dairy products meet or exceed federal bacteria regulations prior to delivery to retailers.

Meadow Gold spokeswoman Carissa Tourtelot added that spoiled milk "is not a safety or health issue. It's not harmful, it just won't taste good."

Tourtelot said bacteria levels would need to be far in excess of those discovered by Lee to be discernable by consumers. The company noted that there are no federal bacteria standards for determining when milk is actually spoiled. Determining whether milk is spoiled is based on taste, smell and appearance, Tourtelot said.

Some O'ahu consumers, such as Kailua resident Ronaele Whittington, have complained that milk sometimes spoils prematurely.

"I thought it was me or my refrigerator's fault," Whittington said. "I always pick the milk that has the longest date on it. It just seems so weird."

Once milk leaves the processing plant it must be kept at 40 degrees Fahrenheit or lower to keep bacteria growth low and preserve freshness.

"Anytime milk is kept above that (temperature) you're reducing the shelf life," Tourtelot said.

RANDOM TESTING

Milk tested by Lee was purchased from a variety of O'ahu stores during the winter and spring, he said. The freshest milk was selected based on the product's sell-by date.

The milk was transported to a laboratory in coolers to keep its temperature at or below 39 degrees Fahrenheit, to preserve freshness. Samples then were tested to determine bacteria levels. The higher the bacteria level, the greater the tendency for milk to spoil.

Lee said he found some milk exceeded federal bacteria levels, but his final results — including the amounts and frequency of bacteria discovered — won't be available until late this year. The source of the bacteria could include improper handling of milk prior to testing.

Another possibility is the massive amount of Mainland milk that's imported to Hawai'i, which increases the milk's age and the potential for higher levels of bacteria, Lee said.

Less than 30 percent of Hawai'i's milk is produced locally, which is down from 100 percent in the 1980s.

Pacific Dairy is the only commercial dairy remaining on O'ahu, and it plans to close this summer. After that, virtually all milk sold on O'ahu will be imported.

Most milk from the Mainland is repasteurized, or reprocessed, before being sold to consumers. That adds about eight days to the age of imported Mainland milk, which can be between 25 to 30 days old by the time it reaches its shelf expiration date.

"It is unlikely that any state in the nation sees 25- to 30-day milk from a cow (to) consumer unless it was ultrapasteurized," Lee said. "However, no law is broken because none exist. There is no limit in terms of how long you can keep milk on the shelf to sell."

Meadow Gold is free to set its own milk expiration dates, which typically range from 17 to 19 days of shelf life.

Meadow Gold Dairies has a history of "very, very few" regulatory violations, according to state health officials. The state Department of Health tests Meadow Gold dairy products once a month at the plant and inspects the O'ahu milk processor's facility each quarter. In addition, Meadow Gold conducts its own stringent, quality control tests, the company said.

Although the state Department of Health fields sporadic complaints from consumers that milk prematurely spoils, there's nothing that indicates any widescale milk spoilage problems on O'ahu, said Peter Oshiro, plan review and standards office supervisor for the state Department of Health.

The federal regulatory limit for pasteurized milk is 20,000 visible, countable colonies of bacteria per milliliter of milk for as long as the milk is sold. However, the state does not test the bacteria level of milk after it leaves Meadow Gold's gates.

"That may be (the limit), but in the real world it's never sampled at the retail level, so it's never enforced," Oshiro said. "The reason why is because once the delivery is accepted by the supermarket, the milk plant really can't be held responsible."

Bacteria levels well in excess of 20,000 colonies per milliliter, which Lee said he discovered in his study, won't hurt milk consumers, Oshiro said.

Sour milk is still safe to drink and is not a health concern.

"I've never heard of sour milk causing (gastrointestinal) problems," Oshiro said.

No tests were conducted on long-lasting ultrapasteurized milk.

ORGANIC LEVELS LOW

According to Lee, the lowest bacteria counts were found in pricey organic milk, which is typically flown to Hawai'i in packaged form. Bacteria levels of Big Island milk also were below federal limits past the milk's stated expiration date.

Hawai'i isn't immune to milk-related public health issues. State officials discovered unacceptably high levels of the pesticide heptachlor in milk in the early 1980s. The source was ultimately traced to cattle feed that included pineapple leaves.

Honolulu attorney Ken Wong, who represented a local pineapple company in an ensuing heptachlor lawsuit, said state regulators need to look at issues of milk quality and freshness more closely.

"I think the (spoiling) problem started occurring when the local farms went out of business and they started bringing in this milk from the Mainland," he said. "We still have a problem with milk here. There seems to be a problem with bringing in old milk basically and repasteurizing it and treating it as if it's fresh milk produced locally that will last the same amount of time as milk produced in the Islands."

FEW COMPLAINTS

Despite concerns about milk freshness, local retailers, including Foodland Super Market and Shima's Market in Waimanalo, said few consumers complain about spoiled milk.

"It's a rare occurrence," said Ron Shima, owner of Shima's. When spoiling occurs, "We always give the money back; it's not a problem."

However, Shima acknowledged that consumers may not always bother to return unused, spoiled milk.

Kailua's Whittington said she's only returned spoiled milk twice.

"I was afraid (store officials) would think I was a scam artist," she said.

Many instances of milk spoiling also may be a matter of improper handling, UH's Lee said.

"People go to Costco and they can't resist the hot dog and pizza," he said. "So they stand in line, eat their hot dog and pizza before they go back" home. "That actually increases the temperature of the milk" and the potential to spoil, he said.

Consumers also can prevent milk spoilage by consuming milk quickly.

Sandra Perreira, a secretary from Pacific Palisades, has another solution. "I split it into one quart containers and freeze it because otherwise it will go bad," she said.

Reach Sean Hao at shao@honoluluadvertiser.com.