Food safety principles in cider and novel juice processing technology

One of the most popular ways to add value to fruit crops is to press them. Juices and ciders are especially lucrative for those with orchards, but maintaining the safety of those products is paramount.

Randy Worobo, a professor of food science at Cornell University, spoke about food safety principles in cider and novel juice processing technology at the most recent Great Lakes Expo.

He noted it’s been 25 years since the implementation of hazard analysis critical control points (HACCP), a management system in which food safety is addressed through the analysis and control of biological, chemical and physical hazards from raw material production, procurement and handling to manufacturing, distribution and consumption of finished products.

As it is a thorough FDA set of guidelines, Worobo provided a condensed version of juice HACCP regulations. Notably, a greater than 5-log pathogen reduction step (reducing the number of pathogens by 100,000 times) is required unless a product is exempt (for example, shelf stable juices and concentrates); there must be metal and glass control; and low acid juices must address Clostridium botulinum control.

Additionally, there must be patulin control via culling for apple cider and juice. Worobo said patulin is an issue because of fruit imports from China, and it pertains to dairies that share pasteurizers for juice.

The common mold Penicillium expansum invades wounded apples, causing blue mold decay and ensuing the production of patulin, a mycotoxin that negatively affects human health. Patulin is a lactone that is heat-stable, so it is not destroyed by pasteurization or thermal denaturation.

Patulin is often found in increasing levels between January and April – the longer fresh cider is kept in cold storage, the more likely it will be found. HACCP needs to address testing issues in this window and outline some remediation issues as well, Worobo said. He recommended improving culling efficiency later in the year to decrease the risk of patulin.

There are also issues that arise from state to state. The FDA offers federal guidance, but in New York, for example, there is a 5-log requirement for all apple cider; in Maine, there must be labeling of thermally processed “cider.”

Despite the red tape, HACCP is working. Since it went into effect, there have been about 500 fewer illness cases per year from unsafe juices and ciders.

However, there is another outside force to contend with for safety: consumer trends. Worobo cited an aversion to “chemical” additives and GMOs (often fueled by social media and TV personality misinformation); the quest for high nutrition composition; and the retention of flavors, nutrients and characters.

“Consumers want fresh – minimally or unprocessed food,” he noted. For proof, look at the popularity of the “raw food” diet movement.

Technologies to Meet Trends

“Adapt or perish, now as ever, is nature’s inexorable imperative,” said author H.G. Wells, and that’s what cidermakers must do to keep up with consumer trends.

Worobo listed some natural food sources that work as preservatives, such as cranberry extracts for benzoic acid, celery extracts for nitrites and nitrates, bacterial fermentates (like Microguard™) and mushroom extracts (like Nagardo™, which is good for about six months of shelf stability). Antioxidants such as rhubarb and citrus extracts work for anti-browning. And there lots of plant-based sources for juice coloring.

As far as processing technologies go, there are some tried-and-true methods and some new ones being honed for future use. Pasteurization is the current go-to option.

High pressure processing (HPP) exists but doesn’t really make sense for smaller cider operations, according to Worobo, as it costs about $600,000 for a 55-gallon high pressure processor. It is a non-thermal processing technology which has been commercialized by Hiperbaric and Avure. HPP is good for refrigerated and extended shelf life products and the retention of “fresh” qualities and nutrition. The enzymatic activity of foods is minimally affected with HPP.

HPP also provides good inactivation against vegetative bacteria, yeast and mold – but it is not effective against bacterial spores (like C. botulinim, C. perfringens, B. cereus, etc.).

Ultraviolet and pulsed light technologies are still being developed, as are pulsed electric fields and ionized plasma (which has not been commercialized yet).

“Ultraviolet light processing is more common in small juice operations,” Worobo said, and it works well with clear juices. To be effective, juice requires 14.2 millijoules per square centimeter (a measurement of energy received per unit area) to meet that HACCP 5-log performance standard. He mentioned several CiderSure models currently doing the work in UV light processing.

Pulsed electric field (PEF) tech uses electrical arcing and thermalization to result in the destabilization of microbial membranes and thermal inactivation. It has liquid applications and solid PEF consumer units are being developed, per Worobo.

The Plasma Coalition says plasmas underlie numerous important technological applications, including providing “the foundation for important potential applications such as … pollution control and removal of hazardous chemicals.”

When it comes to cider safety, though, “ionized plasma still being worked out,” Worobo said.

To learn more about the work his Worobo Lab is doing in the field of food safety, visit blogs.cornell.edu/worobolab.

by Courtney Llewellyn