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Pilot plant helps Salmonella in spices research

By Joe Whitworth+

20-Mar-2014
Last updated on 20-Mar-2014 at 18:13 GMT

Photo: Virginia Tech. Salmonella in spices is the focus of the research
Photo: Virginia Tech. Salmonella in spices is the focus of the research

Research on how spices become contaminated with Salmonella has got a boost with the opening of a new building at Virginia Tech.  

Monica Ponder, assistant professor of food science and technology in the College of Agriculture and Life Sciences, is looking at how and why spices become contaminated with Salmonella.

The biosecurity level 2 pilot plant will allow her to test large pieces of equipment used for drying spices like those used for industrial processing.

The 93,860-square-foot building has some equipment – including a mock deli set-up.

Pilot plant

Ponder told FoodQualityNews.com that they are using strains isolated directly from spices and US outbreaks.

“In the new building we have a food safety pilot plant which we can use to study how foods are contaminated when firms bring in their process equipment," she said.

“If they are interested in pasteurization or spray drying we can work with the product and identify the contaminated product and help companies with their processes.

“The scale-up between the lab and the real world in food processing plants will enable us to have a safer food supply…including the capability to expand beyond lab scale to pilot plant experiments.”

Ponder was part of a team which put germs that form biofilms for self-protection in dry conditions under the spotlight to understand the benefits last year .

Biofilms role

She’s studying how the pathogen travels through the supply chain tightly adhered to whole spices within biofilms.  

Biofilms formed during growth or during processing may improve survival of Salmonella by encasing it within layers of polysaccharides, protecting the cells.

While Salmonella isolated from spices and other low-moisture foods in disease outbreaks is lower than meat, the potency is much greater, indicating the lower moisture environments such as those where spices are processed tend to increase the virulence of the pathogen.

A project for Ponder and her team involves looking at biofilms and the effect of using ethylene oxide and steam as a treatment on whole black peppercorns.

Hygiene and sanitation are challenges to determine how frequently to clean equipment and is it effective when you use disinfectant and sanitize," said Ponder.

“Cross contamination and sanitation needs to be understood to follow the spread of pathogens.”  

“[The] black pepper outbreak in 2009 people didn’t think about low moisture foods and how organisms survive.

“Spices are a concern because they are often added as a seasoning after the critical control point such as heating or another thermal process and you could potentially be contaminating your product.”

Spices in USA

The US is one of the world’s largest spice importers, bringing in 326 kilotons in 2012 valued at $1.1bn.

Spices are typically grown in developing countries where opportunities for tainting the product from infected workers and pests are increased due to poorer sanitation practices.

There is minimal processing after harvest to destroy human pathogens, which presents a contamination risk from Salmonella because spices are frequently added to finished products.

The Food and Drug Administration (FDA) has completed a draft risk profile on pathogens and filth in spices due to outbreaks caused by the consumption of Salmonella-contaminated spices.

The agency said current pathogen control measures may not adequately protect public health .

Comments on the draft risk profile closed earlier this month.

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