Combining technologies to make safer spinach

Charlyn Fargo, Contributor

University of Illinois scientists have found a way to boost current industry capabilities when it comes to reducing the number of E. coli 0157:H7 cells that may live undetected on spinach leaves.

"By combining continuous ultrasound treatment with chlorine washing, we can reduce the total number of food-borne pathogenic bacteria by over 99.99 per cent," said Hao Feng, a U of I professor of food science and human nutrition.

According to Feng, the US Department of Agriculture is looking for proposed technologies that can achieve a four- to six-log reduction in pathogen cells (a six-log reduction would achieve a millionfold reduction in pathogenic bacteria). The food-processing industry can now achieve a one log or tenfold reduction. In comparison, the U of I technique yields a four log reduction.

"Combining technologies is the key to bridging the gap between our current capacity and what USDA would like to see. The use of ultrasound exposure during chlorine washing gives the industry a way to significantly enhance microbial safety," he said.

Feng's pilot-scale system uses three pairs of large-area ultrasonic transducer boxes to form a channel through which ultrasound is provided to spinach leaves that are undergoing a continuous-flow chlorine wash. Spatial uniformity of ultrasound distribution was confirmed by tests using metallic foil. Continuous flow and uniformity of the field are key elements in the success of the process, Feng said.

"Previous work with ultrasound used a tank or a medical-style probe, which doesn't provide consistent and even distribution," Feng added.

"Placement of the produce as it makes its way through the channel turns out to be very important. We had to find ways to make sure that leaves received similar exposure to ultrasound, taking care to minimise the chance that one leaf would block a nearby leaf's exposure to the sound waves."

If even part of a leaf escaped the full ultrasonic treatment, it could contaminate the rest of the produce, he said.

Feng and his team have used the technique on iceberg and romaine lettuce, as well as spinach, with similar results.

Information and article courtesy of the University of Illinois and Medical News Today.

Calorie density and weight management

Q I've been hearing about calorie density and its effect on weight. If I want to lose weight, is it better to focus on calorie density and also count fat and calories, or is changing calorie density enough?

A You will usually reduce fat and calories when you focus on calorie density because you are filling up on foods with fewer calories per bite. The same size portion of different foods can be very different in calories: for example, one cup of broccoli has only 60 calories compared to one cup of white rice at 200 calories. Studies show that each individual tends to eat about the same amount of food from day to day, so by including a large proportion of foods that are low in calorie density, you can feel full while eating fewer calories. Fat content is part of what determines a food's calorie density, so when you eat foods low in calorie density, you already are limiting fat.

In my experience, the simpler something is, the more easily people tend to succeed in following the advice. For example, start by eating at least 10 foods each day that are low in calorie density (such as vegetables, fruits, whole grains and beans) and eat no more than two servings of foods highest in calorie density (such as pastry and fried foods).

The trick for success is to make sure that you are truly reshaping your usual eating choices replacing foods concentrated in calories with foods low in calorie density. If you just add more vegetables, you'll be getting more nutrients, but without cutting calories, you won't lose weight.

Eating plenty of foods low in calorie density should satisfy your hunger, helping you limit calories. Do keep in mind that sometimes we eat more than we need not because we're hungry, but because there's extra food or we are eating out of boredom or stress. If those are tendencies you experience often, address those problems directly; if you need help, look for a registered dietitian experienced in dealing with emotional or other non-hunger eating.

Recipe

Cooking Light has a new cookbook called, The New Way to Cook Light. The secret is fresh food and bold flavours. It features more and different vegetables, more whole grains, smaller portions of meat and different species of fish with lighter sauces. The new paradigm is food that is soul satisfying, deeply flavoured and real, rather than simply lighter versions with reduced fat this and that. Here's a recipe to try.

Spicy Honey-Brushed Chicken Thighs

2 tsps garlic powder

2 tsp chili powder

1 tsp ground cumin

1 tsp paprika

3/4 tsp salt

1/2 tsp ground red pepper

8 skinless, boneless chicken thighs

Cooking spray

6 tbs honey

2 tsp cider vinegar

Preheat broiler. Combine first six ingredients in a large bowl. Add chicken to bowl, toss to coat. Place chicken on a broiler pan coated with cooking spray. Broil five minutes on each side. Combine honey and vinegar in a small bowl, stirring well. Remove chicken from oven; brush 1/4 -cup honey mixture over chicken. Broil 1 minute. Remove from oven and turn over.

Brush chicken with remaining honey mixture. Broil an additional 1 minute or until chicken is done. Serves four (serving size: two chicken thighs).

Per serving: 321 calories, 28 grams protein, 27.9 grams carbohydrate, 11 grams fat, 99 milligrams cholesterol, .5 grams fibre, 528 milligrams sodium.

Information courtesy of the American Institute for Cancer Research.

Charlyn Fargo is a registered dietitian from Springfield, Illinois. For comments or questions, contact her at charfarg@aol.com. Follow her on Twitter @ NutritionRD. To find out more about Charlyn Fargo and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.