Safeguarding organic pork with natural nitrate and antimicrobials

Consumers' enthusiasm for natural and organic food products extends to cured pork products such as hams, bacon and frankfurters. But products can't be labelled as natural or organic if they contain preservatives. That means two traditional curing agents for pork - nitrite and nitrate - aren’t allowed in natural and organic versions.

To work around that problem, Iowa State University researcher Joe Sebranek explained, industry found that vegetable juice powder could provide a natural source of nitrate to serve as a curing agent and still be classified as a natural source. But there still wouldn’t be as much nitrite in the product as in a conventionally cured product and it would be at greater risk from bacterial pathogens.

Sebranek, a professor of animal science, food science and human nutrition, researched the problem with support from the US Food Safety Consortium and found a solution. Take a couple of natural antimicrobial ingredients - vinegar with lactate and vinegar with lemon powder - and incorporate them into the naturally cured pork products.

The result was that bacterial pathogens such as Listeria monocytogenes in the naturally cured pork products were inhibited, though still not to an equivalent level as in conventionally cured pork products.

"With natural and organic products you're limited to ingredients that qualify as natural or organic, respectively," Sebranek said. "If you use something that is traditionally used as a preservative, that's not permitted in a natural product. With a naturally fermented vinegar product, you have a mixture of organic acids. It's not typically used as a preservative but it provides some of the organic acids that are recognised antimicrobials. There’s a mixture in that kind of a product that essentially provides a preservative effect."

ISU researchers plan to examine other natural antimicrobial ingredients to see what would also be effective. Sebranek said there had already been some interesting results with cranberry extracts.

"Cranberry has a number of antioxidants and potential antimicrobial compounds," he said. "We're trying to get that more specifically identified. There are a number of different kinds of extracts and compounds that are natural, which is the first thing that's necessary. Maybe you could combine enough antimicrobials to get you back to the same level of protection against pathogens as with the conventionally cured product. That would be our ultimate goal."

There would be potential practical application at the industrial level if the research leads to something that’s economical. "And things like cranberry are an attractive kind of label addition too," Sebranek said.