The Research Column

Bacterial contamination of foods may lead to reduced shelf life due to outgrowth of spoilage organisms and, in the case of pathogens, to food borne illness upon consumption of contaminated products. To inactivate bacteria that may grow in finished products, many food products undergo heat treatment. Pasteurisation results in inactivation of vegetative cells. However, bacterial spores will survive such treatments, after which they may germinate and grow in finished liquid products.

The nutritional and pharmacological advantages of chromium (Cr) for animals and humans have been well established. Trivalent Cr is a component of chromodulin which is involved with insulin regulation, and thereby associated with the metabolism of carbohydrates, protein and lipids. The signs of Cr deficiency include impaired nutrient metabolism, lower sensitivity of the peripheral tissues to insulin, compromised immunity and decreased weight gain and health status, specifically under stressful conditions.

The utilization of functional foods has increased since the last decade. In many instances they form part of the daily diet where they have the potential to lessen the risk of disease along with their accepted nutritional efficacy. The beneficial effects are due to the presence of physiologically active components, which have the ability to lessen the threat of chronic diseases.

Standardization of terminology is important as people often develop definitions which  the meaning thereof is not recognized or understood by others, or they use one term for different activities or functions. One such term is culling which is used in different ways leading to confusion or misinterpretation. To address this Dr J. Fetrow and colleagues were commissioned by the American Dairy Science Association to address the confusion and come up with recommendations.

When products derived from the coagulation of milk are produced, liquid whey results which may account for 80 to 90% of the milk which originally entered the dairy manufacturing facility and about 50% of the milk nutrients. The composition of the whey varies depending on the end product, and the manufacturer’s production process. Hard cheeses (e.g. Cheddar) result in sweet whey, with a relatively high pH (more than 5.8), high protein and low mineral contents. Fresh cheese and strained yogurts ( e.g.

Greenhouse gases (GHG), including methane (CH4), play an important role in global warming. Methane has 28 times the global warming potential of CO2. Although in SA the figures are much lower due to the small size of the dairy industry, the global dairy supply chain produces 20% of the livestock-sector’s GHG, and 46.5% of that is from enteric CH4.

Serum total Ca (tCa) and whole-blood ionized Ca (iCa) were monitored in 24 multi-lactation Holstein cows after parturition. Pre-calving diets were formulated with a positive dietary cation-anion difference of 172 mEq per kg of DM and contained 4.1 g of Ca per kg of DM. At calving, cows were blocked by calving sequence and blood Ca status as either normo-calcaemic (cut-off threshold of iCa equal or more than 1.10 mmol per L) or hypocalcaemic (cut-off threshold of iCa less than 1.10 mmol per L).

In the studies, primary research papers were found through targeted Web of Science searches, the reference lists of recent reviews for each topic, and the reference lists of papers identified from these sources. Studies were included if they were published in English, the full text was accessible, and they compared treatments with and without contact between dairy cows and calves for a specified period. The resulting manuscripts underwent a 4-step appraisal process, and further manuscripts were sourced from reference lists.

A fermentation product of the yeast Saccharomyces cerevisiae (SC), has been widely used in diets of dairy cows with the aim of increasing production performance and stabilizing rumen pH. Several studies have reported positive effects such as increased DMI and milk production when cows were fed SC, but the results are inconclusive. Also,  the possible interaction between the fermentability of the basal diet and SC supplementation on DMI has not yet been addressed. Therefore, the objective of a study by Dr W.

South Africa is 13th on the list of highest emitters of global greenhouse gases GHG). Despite this is Africa still the smallest contributor to GHG emissions among the continents, yet the most vulnerable to the impacts of climate change. The effects will not be limited to rising temperatures and changing rainfall patterns, but also to increased severity and frequency of droughts, heat stress and floods. Agriculture is not only impacted upon by climate change but also contributes to global warming.