Food Protection Trends

Abstracts - May 2005

The Bactericidal Effects of Lactic Acid and Trisodium Phosphate on Salmonella Enteritidis Serotype pt4, Total Viable Counts and Counts of Enterobacteriaceae

Effectiveness of Trisodium Phosphate, Lactic Acid and Commercial Antimicrobials against Pathogenic Bacteria on Chicken Skin

Farm Food Safety Practices: A Survey of New England Growers

Theo S. Kanellos 1 and Angeliki R. BurrieL 2*

1-Royal Veterinary College, Boltons Park, Hawkshead Road, Potters Bar, Herts, EN6 1NB, UK;
2-Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece

SUMMARY
A common practice in the food industry, decontamination of broiler meat, is based on important public health concerns. A frequently used decontaminant is lactic acid (LA), whereas trisodium phosphate (TSP) is a recent and very promising addition to the permitted agents. In this study, we evaluated the bactericidal activities of LA and TSP against experimentally or naturally occurring Enterobacteriaceae, including Salmonella spp., and the total viable counts of bacteria. Both agents significantly reduced the levels of Salmonella Enteritidis serotype pt4 in experimentally contaminated chicken drumsticks. Reductions in bacterial numbers ranged from 0.50 to 0.75 log 10 for LA and 0.80 to 1.80 log 10 for TSP, depending on treatment scheme and time of exposure. The log 10 reductions of total viable counts (TVC) and counts of Enterobacteriaceae normally contaminating the skin of poultry drumsticks, ranged from 0.67 to 1.47 for LA and from 1.72 to 3.43 for TSP. The reductions were statistically significant (P < 0.01) in favor of TSP when the two agents were compared. As expected, LA reduced the pH of skin (normally 6.6–6.9) to values below normal (5.8 – 6.3); in contrast, TSP increased the chicken skin’s pH (7.0 – 7.8).

Effectiveness of Trisodium Phosphate, Lactic Acid and Commercial Antimicrobials against Pathogenic Bacteria on Chicken Skin

Ghadeer Mehyar, Gregory Blank, Jung H. Han, Arnold Hydamaka, and Richard A. Holley*

Department of Food Science, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada

SUMMARY
Treatments were evaluated for their effectiveness in reducing the numbers of inoculated zoonotic bacteria on the skin of chicken drumettes. Antimicrobial treatments were applied to chilled and unchilled drumettes, singly or in a dual sequence, by dipping before or after bacterial inoculation. First, 10% (w/v) trisodium phosphate (TSP) or 3% (v/v) lactic acid (LA), with or without 2% (w/v) NaCl, were used against Escherichia coli O157:H7. Second, TSP and proprietary products Sanova (acidified sodium chlorite), Safe 2O (acidified calcium sulfate), Cecure (cetylpyridinium chloride, CPC) and Inspexx 100 (peroxyacetic acid) were used on drumettes against E. coli O157:H7, Campylobacter jejuni or a cocktail containing two strains of Salmonella Typhimurium and one strain of S. Heidelberg. Third, selected antimicrobials were evaluated for their ability to control growth of the naturally occurring psychrotrophs on chicken skin and to extend shelf life. Fourth, food grade carbohydrate biopolymers were used as carriers to enhance activity of TSP and Sanova. TSP was twice as effective as LA in reducing the numbers of viable E. coli O157:H7 on chicken skin (>2 log cfu/g reduction by TSP) with exposure of 1 min when treated drumettes were stored 24 h at 4ºC. Exposures > 20 min did not increase reductions with either treatment. TSP alone or LA followed by TSP (which maintained the skin pH at ≥ 10) gave greater reductions of E. coli O157:H7 than LA alone. Antimicrobial treatments (TSP, Sanova, Safe 2O, Cecure and Inspexx 100) were more effective against tested bacteria when applied on warm (unchilled) drumettes before bacteria were added. The reductions in numbers of Salmonella, C. jejuni and E. coli O157:H7 were not significantly different among antimicrobials, but reductions with TSP, Sanova and Safe 2O were generally greater than with Cecure and Inspexx 100. Dual treatments of Cecure with other antimicrobials against the Salmonella cocktail increased bacterial reductions, particularly when Cecure was used last; however, reductions were not significantly different from those with dual treatment with Cecure. Bacterial reductions following treatment with TSP and Sanova appeared related to the high or low pH values these generated. All treatments delayed the growth of pseudomonads and psychrotrophs naturally present on chicken skin when samples were stored aerobically at 7ºC. Sanova, 10% TSP and Safe 2O delayed growth slightly better than Cecure or Inspexx 100, but all antimicrobials extended product shelf life by about 3 d. Carbohydrate biopolymers (TSP in guar or locust bean gum and Sanova in pectin or carboxymethyl cellulose did not enhance antimicrobial action against the Salmonella cocktail inoculated on chicken skin drumettes stored for 72 h at 4°C.

Farm Food Safety Practices: A Survey of New England Growers

Nancy Cohen,* 1 Craig S. Hollingsworth, 2 Rita Brennan Olson, 1 Mary Jane Laus, 1 and William M. Coli 2

1- Department of Nutrition, University of Massachusetts, Amherst, MA 01003, USA;
2- Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, MA 01003, USA

SUMMARY
Fresh produce carries the risk of foodborne illness caused by microbial contamination during many aspects of its production, harvest, post-harvest handling, transportation, and marketing. The purpose of this study was to identify and measure the adoption of grower practices in New England related to safe food handling guidelines. Questionnaires were mailed to 602 farms in the six New England states, asking questions related to the adoption of food safety practices, including those involving water, manure and biosolids, worker hygiene, field sanitation, harvest and storage, packing and processing, pick-your-own operations and record keeping. The response rate for the survey was 49%.