Southeast Asia's import demand for skim milk powder: Implications for US exporters

Flow of spore-forming bacteria between suppliers of dairy powders and users in some developing countries: challenges and perspectives

Abstract

Spore-forming bacteria are common contaminants of milk powder and processing lines and a major concern for the dairy industry. This dairy-associated microflora was studied extensively and well characterized in developed countries (exporters of milk powder), compared to developing countries (importers). Thereby, the quality issues affecting dairy powders and derived products are not fully controlled in developing countries. That is the case in Algeria, where recombined or reconstituted pasteurized milk is of low quality, reduced shelf-life, and the related dairies faced recurrent contaminations due to spores and biofilms. The transfer of spore-forming bacteria from exporters of dairy powders to importers in developing countries is an interesting topic, not thoroughly investigated. In addition, milk powder-based products are growing worldwide and their attributes, processes and technologies need to be better understood and controlled. This review analyzes issues affecting milk powder quality, based on few studies from developing countries in comparison with current knowledge, and emphasis on the case in Algeria. It provides information on how spore-forming bacteria and their biofilms affect the quality and shelf-life of recombined pasteurized milk produced in Algeria and compromise hygiene conditions in local dairy plants. Challenges and perspectives for better management of spore transfer from exporters of dairy powders to importers in developing countries are thereby outlined.

Highlights

The presence of spore-forming bacteria in milk powder is a serious safety issue.Spores are not well known, characterized and controlled in importers from developing countries.Spores cause recurrent contamination of pasteurized milk and biofilm issues in Algerian dairies.Challenges are how to reduce the flow of spores in milk powder trade.Perspectives on identification targeting predominant spores and improvement of biofilm removal.

Lactoferrin as an antimicrobial against Salmonella enterica and Escherichia coli O157:H7 in raw milk

Improper storage conditions or processing of milk leads to potential spoilage and illness, due in part to temperature abuse, allowing bacteria present to grow and spoil the product. However, certain proteins naturally found in raw milk, such as lactoferrin, have reported antibacterial properties. The levels of lactoferrin required to effectively inhibit growth of pathogens have not been investigated thoroughly. This study aimed to examine various concentrations of lactoferrin as a potential biopreservative and as an antimicrobial against the common dairy pathogens Salmonella enterica and Escherichia coli O157:H7. Minimum inhibitory concentration assays were conducted on raw bovine milk in which the bacteria were exposed to varying concentrations of lactoferrin. In the raw milk system, the growth of E. coli O157:H7 was significantly decreased at levels greater than 14.05 mg/mL lactoferrin based on the reduction of tetrazolium salts. For S. enterica, only lactoferrin concentrations at or above 112.5 mg/mL in the milk resulted in reduced growth. Taken together, these results indicate that lactoferrin may have biopreservative potential. To fully examine the practicality and effectiveness of lactoferrin as an antimicrobial additive, a similar study should be conducted using additional (gram-positive) pathogens, such as Bacillus cereus and Listeria monocytogenes. If effective, lactoferrin could prolong the shelf life of dairy products and help reduce the incidence of foodborne illnesses in developing countries with limited refrigeration capability.

Bactéries sporulées et biofilms : un problème récurrent dans les lignes de production de lait reconstitué ou recombiné pasteurisé

In the dairy industry, bacterial contaminants persist on equipment surfaces due to spore and biofilm formation. These are involved in cross-contamination problems that affect the quality of processed products and limit their life. The pasteurization process, in which milk is submitted to moderate heat treatment, is inefficient against bacterial spores. The most prevalent sporulated bacteria belong to Bacillus and related genera. The situation is more complicated in countries where pasteurized milk is derived from imported milk powder originally contaminated by bacterial spores. Studies have shown biofilm formation on dairy equipment by mesophilic strains from the group Bacillus cereus and thermophilic strains from the genus Geobacillus. These biofilms are resistant to cleaning procedures and are sources of chronic contamination of pasteurized milk. This review analyzes the dairy situation in Algeria exposed to sporulated flora and derived biofilm problems, with the aim of proposing efficient solutions in the light of current knowledge. [Journal translation].