Food Science Research: June/July 2020

Microbial Quality and Safety of Milk and Milk Products

With the advent of metagenomic studies, our knowledge on the microbiota of milk and milk products, especially as affected by the environment, production, and storage parameters, has increased. Milk quality depends on chemical parameters (fat and protein content and absence of inhibitory substances), as well as microbial and somatic cells counts, and affects the price of milk. The effects of hygiene and effective cooling on the spoilage microbiota have shown that proteolytic and lipolytic bacteria such as Pseudomonas or Acinetobacter spp. predominate the spoilage bacterial populations. These bacteria can produce heat‐stable proteases and lipases, which remain active after pasteurization and, thus, can spoil the milk during prolonged storage. Additionally, milk can become contaminated after pasteurization and therefore there is still a high demand on developing better cleaning and sanitation regimes and equipment, as well as test systems to (quantitatively) detect relevant pathogenic or spoilage microorganisms. Raw milk and raw milk cheese consumption is also increasing worldwide with the growing demand of minimally processed, sustainable, healthy, and local foods. In this context, emerging and re‐emerging pathogens once again represent a major food safety challenge. This review aims to provide an overview of the major microbial hazards occurring in the 21st century. Comprehensive Reviews in Food Science and Food Safety, published online on May 23, 2020. Read the full journal article here.

High‐Protein Rice Flour in Development of Gluten‐Free Muffins

Hypoallergenic rice flour is typically used in gluten-free (GF) products. New rice varieties with greater protein were recently developed. Physicochemical and sensory properties of white and brown high‐protein rice flours (HPRFs) and muffins were compared to commercial rice flours. The sensory color of white high‐protein rice muffin was favored. Other attributes were not statistically different between samples. HPRF muffins had greater frequencies of “just about right” levels for muffin crumbliness, moistness, and softness than the commercial control. Purchase intent was greater for both HPRF muffins than commercial brown rice muffins. Purchase intent increased further by 9 to 12 percent, after information that the products were gluten free and made with naturally higher protein rice flour was displayed. This study shows that greater protein content rice flour can be used to make gluten‐free (GF) muffins that are acceptable to consumers. This information could be used to market GF food products if increased protein ingredient claims are included. Journal of Food Science. Vol. 85, No. 5, May 2020, pages 1397-1402. Read the full journal article here.

Edible Coatings to Inactivate Foodborne Pathogens on Fresh‐Cut Apples

Multiple formulations of edible coating solutions were developed and evaluated for their ability to maintain the quality and minimize populations of foodborne bacteria on fresh‐cut apples. Fresh‐cut apples were artificially inoculated with Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes, and dip‐treated with coating solutions. Changes in populations of pathogens and molds and yeasts (M&Y) were evaluated after solution treatments and during storage at 4°C for 35 days. Changes in color, texture firmness, and weight loss during storage were also determined. Among the formulations, the solution containing 1 percent of three organic acids (acetic, lactic, and levulinic acids), 2 percent N‐acetyl‐l‐cysteine or L‐cysteine with 0.5 percent chitosan demonstrated the best effectiveness for the simultaneous reduction of pathogenic and spoilage microorganisms, control of browning, and maintenance of the quality of fresh‐cut apples. The treated apple slices had nondetectable pathogens and M&Y (<1 log CFU) and the least quality changes for 35‐day storage. The developed solutions can be used at processing plants, retail stores, or homes to protect fresh‐cut apples or other fresh‐cut fruits and vegetables from microbiological and quality deterioration. Journal of Food Safety, published online ahead of print on April 6, 2020. Read the full journal article here.